It's easy to get started eliminating answer choices in this case because of the clear lack of subject verb agreement in three of them. In A, D and E, the singular noun, pattern, is combined with a plural verb, are. So those three choices are all out. The trick is, of course, to recognize that the subject is pattern, rather than spots. of whisker spots merely modifies pattern.

So we are already down to B versus C.

In C there are two issues. In C, means of identification for life is ambiguous. Does it mean that life is being identified or that the animal has the identification for life or that the identification is somehow for life? Also, in C being both unique and unchanging is far from what it modifies, making the sentence awkward and the connection between modifier and what it modifies unclear.

There is also a commonly held idea that the use of the word being in a GMAT answer choice tends to make that choice wrong. That use might be a red flag, but be careful about using the use of being as a decision point, because there are times when using being makes sense. I didn't even bother worrying about that issue in this case because there were other, clear, ways to eliminate C.

So the best answer is B.