A car starts from rest and moves with uniform acceleration a on a straight road from time t = 0 to t = T. After that, a constant deceleration brings it to rest. In this process the average speed of the car is [MP PMT 2004]

• A.              \[\frac{aT}{4}\]                    
• B.                         \[\frac{3aT}{2}\]            
• C.                                  \[\frac{aT}{2}\]
• D.                                  \[aT\]