The correct option is C T1<T2
Since air resistance is not ignored, thus while going up, resistance acts opposite to velocity or in downwards direction. Thus net acceleration is in downwards direction and is equal to a+g, which opposes motion. Thus time taken will reduce to bring it to stop. While coming down, r acts opposite to velocity , i.e. upwards, thus net force or acceleration is downwards =a−g. Since acceleration is lower in this case, time will not decrease that much as compared to a+g. Thus T1 will be less than T2