What is the best way to combine the information in the two sentences below? mercedes threw andrea a surprise birthday party last night. andrea is mercedes' best friend. a. mercedes threw andrea, mercedes' best friend, a surprise birthday party last night. b. mercedes threw andrea a surprise birthday party last night, but andrea is mercedes' best friend. c. mercedes threw andrea a surprise birthday party last night, when andrea is mercedes' best friend. d. mercedes threw andrea a surprise birthday party last night, andrea is mercedes' best friend.

The answer is A. Mercedes threw Andrea, Mercedes' best friend, a surprise party last night.  This choice uses an appositive ("Andrea, Mercedes' best friend,") to combine the two sentences.  An appositive is a phrase separated from the rest of the sentence by commas that describes something (in this case Andrea).

Choices B and C are incorrect because the uses of the words "but" and "when" to combine the sentences do not make logical sense.  Choice D is incorrect because it uses a comma to combine the sentences without a conjunction, creating a run-on sentence.

Hope this helps!

a source card is mage during research to tell the facts about the source one is using.

what are the phrases to choose from?