(1)

Experiment of throwing different spherical balls from certian height:

Ignore the air resistance, hence the drag resistance due to air is not considered.

For a freely falling body, the net force acting on the body is equal to the force due to gravity.

Hence each and every ball moves with same acceleration, that is, accerleration due to the gravity.

Since the balls are dropped from same height and move with same acceleration, they hit the ground at same time.

Hence all the balls will hit at same time.

Option (c) is correct choice.

(2)

Experiment of throwing different spherical balls from certian height:

The drag force due to air is considered.

The net force acting on the body:

Hence the acceleration depends on the ratio of ratio and mass.

Larger the ratio , larger amount of will be subtracted from g, hence the ball will move with less acceleration.

Therefore the object which moves with less acceleration will take the longest time.

Comapre the ratio of Beach Ball, Bowling Ball, Golf Ball and Ping Pong Ball.

Observe the table:

Ratio of Beach ball, Bowling ball, Golf ball and Ping Pong ball are and respectively.

Ratio is large for Beach ball.

Hence acceleration of beach ball is less and it takes longe time to reach the ground.

Option (b) is correct choice.