It's closeness im pretty sure
The Mississippi River has many small tributaries, but its primary tributaries are the Ohio River and the Missouri River. The Amazon River also has a large number of tributaries, including the Rio Negro, which is one of the largest rivers in the world in terms of volume. The Nile’s primary tributary is the Atbara River.
16m -12 - m + 5 = - 52
16m - m = - 52 - 5 + 12
15m = - 45
m = -45 / 15
m = -3
The subject of science is very broad. With that being said, I think there is no official regulatory board that decides the branches of science. Scientific developments are products of joined efforts of different scientists. These scientists could rebuke another's work provided there is evidence. As long as the theory is generally accepted by the scientists and no one rebukes it effectively, then it is a generally accepted fact and everyone adapts it.
Hence, the answer is B.