The correct answer is B. 20.
Current is the flow of charge per unit time. It is measured in amperes (A), where 1 ampere is equal to 1 coulomb per second.
In this question, we are given that a charge of 500 Coulomb flows in 25 seconds. Therefore, the current is 500 / 25 = 20 A.
Option A is incorrect because it is the total charge, not the current.
Option C is incorrect because it is the current if the charge flowed for 1 second, not 25 seconds.
Option D is incorrect because it is the current if the charge was 6250 Coulomb, not 500 Coulomb.