Answer:
The sentence that contains an appositive phrase is sentence B.
Step-by-step explanation:
An appositive phrase is a noun or noun phrase that renames another noun right beside it. Because the information provided by the appositive is nonessential as the meaning of the sentence does not depend on it, it is offset with commas. If you removed the appositive from the sentence, the meaning would be left unchanged (see 1).
1) The safari stopped at an oasis