Out of all given options, “up the mountain” identifies as a prepositional phrase in the given sentence.
Answer: Option B
Explanation:
A prepositional phrase builds with a group of words along with a preposition. A preposition is a word which helps in connecting a noun with a verb, sometimes a verb with an adjective too. In this sentence up the mountain is the prepositional phrase because prepositional phrase can also connect an adjective to a verb, thus making 'up the mountain' as the prepositional phrase.