Explanation:

A fills 4 buckets in 24 minutes. Thus, A fills 1 bucket in 24/4 = 6 minutes

Similarly, B fills 8 buckets in 1 hour. Thus B fills 1 bucket in 60/8 minutes

Similarly, C fills one bucket in 20/2 = 10 minutes

In 2 hours,

Number of buckets filled by A will be = 120/6 = 20 buckets

Number of buckets filled by B will be = 120/ (60/8) = (120 * 8) / 60  = 16 buckets

Number of buckets filled by C will be = 120 / 10 = 12 buckets

Total number of buckets filled = (20 + 16 + 12) = 48 buckets

Total amount of water coming out of the tank = capacity of the tank = 48 * 5 liters = 240 liters

Hence, option 2 is the correct answer.