The lake is full at thirty-two feet. It takes fifteen inches of rain per year to keep the lake at thirty-two feet.

How could you express this situation in conditional terms?

A. The lake is full because it rained fifteen inches this year.
B. If it rains fifteen inches during the year, the lake will be full.
C. The lake needs rain to be full.
D. If it is the end of the year, the lake is full.