Final answer:
"Anyone who needed Louise had to pass behind the shelves" is the independent clause in sentence A; the dependent clause is absent. "The stray cat escaped" is the independent clause in sentence B, and "that was caught by the guard" is the dependent clause. "He should step up" is the independent clause in sentence C, and "who asked that question" is the dependent clause.
Step-by-step explanation:
In sentence A, the independent clause is 'Anyone who needed Louise had to pass behind the shelves' and the dependent clause is not present.
In sentence B, the independent clause is 'The stray cat escaped' and the dependent clause is 'that was caught by the guard'.
In sentence C, the independent clause is 'He should step up' and the dependent clause is 'who asked that question'.