In What Way Are Blue Box and Fraser Box Similar

In what way are Blue Box and Fraser Box similar to each other?

A) They are both irrigated with the water that allows coho salmon to swim in a stationary position.
B) They are both designed to recover coho salmon caught by-catch.
C) They are both irrigated with the flowing water that allows coho salmon to swim against the current.
D) They are both irrigated with the flowing water that allows coho salmon to swim down the current.