<p>After a long period of time negotiating the terms of the merger agreement, the two companies were <strong>finally</strong> able to come to an agreement.</p>
<p>The correct answer is (B) finally. The word "finally" is used to indicate that something happened after a long time or after a series of delays or difficulties. In this sentence, it shows that after a prolonged negotiation process, the two companies were ultimately able to reach an agreement. The other answer choices do not fit the context of the sentence:</p>
<p>(A) commonly: This word means "often" or "frequently" and does not convey the sense of a long negotiation process.</p>
<p>(C) strictly: This word means "exactly" or "precisely" and does not fit the context of negotiations.</p>
<p>(D) plainly: This word means "clearly" or "obviously" and does not convey the idea of a long negotiation process.</p>