A humble request – Please give KUDOS if you like the explanation.
The answer is B.
According to U.S. agricultural statistics, the rate of honeybee colony collapse has slowed over the last several years, the number of which will however continue to decrease unless something drastically changes.
Let us first dissect the sentence.
According to U.S. agricultural statistics, the rate of honeybee colony collapse has slowed over the last several years,
the number of which will however continue to decrease unless something drastically changes.
The correct idiom is the number of colonies
A. years, the number of which will however
The number of which – It is unclear what which refers to.
B. years; the number of colonies, however, will
This is the correct choice.
C. years, however the amount of colonies will
The amount of colonies is an incorrect idiom
D. years; the amount of which will, however,
The amount of colonies is an incorrect idiom
E. years, when the amount of the colonies will, however,
The amount of colonies is an incorrect idiom