She got soaked walking home in the rain yesterday because her umbrella was in her gym locker.

which part of this sentence is a clause?

"she got soaked walking"
"home in the rain yesterday"
"because her umbrella"
"was in her gym locker"

Among your options, there is only one clause, and that would be A. "she got soaked walking."
When it comes to clauses, they need to have a subject (she in A), and a verb (got soaked in A). The other options don't have both the subject and the verb and thus cannot be considered clauses. There is however another clause in this sentence (because her umbrella was in her gym locker), but it is not one of your options. 

The film maker would put sound effects in the film instead of describing the sounds because its a film so most likely sound effects of animals is your answer