Assertion (A) The speed of an aircraft going on route number 1 at a height of 15 km is more than the speed of an aircraft going on route number 1 near sea level. Reason (R) The speed of sound depends on the temperature of the variable medium.

• A. Both A and R are correct and R is the correct explanation of A
• B. Both A and R are correct but R and R is not the correct explanation of A.
• C. A is right but R is wrong
• D. A is wrong but R is right