<p style="">The correct answer is (B) complement.</p><p>The sentence reads, "The acquisition brings together two companies that, while often rivals, actually complement one another in strategic ways." Here, "complement" is used as a verb, meaning that the two companies enhance or improve each other's qualities or strengths, especially in strategic ways.</p><p style="">(A) "complementary" is an adjective that describes things that combine well together, but here we need a verb. </p><p style="">(C) "compliment" is a verb or noun referring to a polite expression of praise or admiration, not a suitable context here.</p><p style="">(D) "compilation" is a noun meaning a collection of various items, documents, etc., and it doesn't fit in this context.</p><p style="">So, (B) "complement" is the appropriate choice, referring to the way the companies benefit each other strategically.</p>