The question is about the canal-carrying capacity of Farakka. This refers to the maximum amount of water that the Farakka canal in India can carry at any given time. The capacity of a canal is typically measured in cusecs, a unit referring to cubic feet per second.

Option 1 suggests that the capacity is 75,000 cusecs, and option 2 suggests it is 70,000 cusecs. Both of these suggest a very high carrying capacity, but they are not correct.

Option 4 suggests that the Farakka canal has a carrying capacity of 35,000 cusecs. While this is a significant amount, it`s too low for the real capacity of Farakka canal.

The correct answer is option 3, which states that the Farakka canal has a carrying capacity of 40,000 cusecs. This capacity is lower than options 1 and 2 but higher than option 4. It`s important to remember this figure as it helps understand the scale and significance of this canal.