The prepositional phrase for this sentence is "go until Friday." The word "go" is a preposition. Think of it as a squirrel and a log. To find a preposition, say "The squirrel (went) [insert preposition] the log." If it makes sense, it is a preposition. Then just find the phrase to go along with it!
Answer:
c. this house is as clean as a whistle
"This is the second activity in the repetition strategy" indicates that the word revisit would be the best word to use to sum up the idea since repetition strategy definitely suggests revisiting. Something which is repeated is done over again so in the act of re-doing it it means it is also re-visited.