Programmer is not responding error

I finished compiling a code, but whenever i try to upload the code it says

Sketch uses 4,766 bytes (14%) of program storage space. Maximum is 32,256 bytes.
Global variables use 396 bytes (19%) of dynamic memory, leaving 1,652 bytes for local variables. Maximum is 2,048 bytes.
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0xdf
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0xdf
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0xdf
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0xdf
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0xdf
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0xdf
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0xdf
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0xdf
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0xdf
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0xdf
Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.

My code is-

#include <AFMotor.h>
#define trigPin 12
#define echoPin 13
AF_DCMotor motor1(1,MOTOR12_64KHZ);
AF_DCMotor motor2(2, MOTOR12_8KHZ);

void setup() {
  Serial.begin(9600);
  Serial.println("Motor test!");
   pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  motor1.setSpeed(105);
motor2.setSpeed (127.5);  
}
 
void loop() {

   long duration, distance;
  digitalWrite(trigPin, LOW); // Added this line
  delayMicroseconds(2); // Added this line
  digitalWrite(trigPin, HIGH);
//  delayMicroseconds(1000); Removed this line
  delayMicroseconds(10); // Added this line
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration/2) / 29.1;
  if (distance < 25) {  // This is where the LED On/Off happens
   Serial.println ("Close Obstacle detected!" );
Serial.println ("Obstacle Details:");
Serial.print ("Distance From Robot is " );
Serial.print ( distance);
Serial.print ( " CM!");

Serial.println (" The obstacle is declared a threat due to close distance. ");
Serial.println (" Turning !");
    motor1.run(FORWARD);
    motor2.run (BACKWARD);

}
  else {
   Serial.println ("No obstacle detected. going forward");
   delay (15);
   motor1.run(FORWARD);
    motor2.run(FORWARD);
  }
}

I am using a arduino uno board and i have tried unplugging the board from the computer, pushing the reset button before uploading, tacking everything off the board, and closing the code and opening up again.

Often this means you have selected the wrong board type.