Directions: In the following question, two statements are given with some words in bold. Which of the following pairs of bold words must be interchanged to make both sentences grammatically correct?

a. Startups were expensive(A), which brought a rapid experience(B) of small privately-owned restaurants and shops on the city streets(C).
b. Going to court can be an encouraged(D), time-consuming, and gut-wrenching proliferation(E) that is best avoided(F).