"Sara and Mary are ... of a mountain climbing club."

• The most suitable word here is members. Members are people who belong to a club or organization.
• Answer: B. members

"They ask their classmates to ... about their hobbies."

• The most logical action in this context is to talk about their hobbies.
• Answer: D. talk

"David plays badminton with his friends two ... a week."

• When referring to the frequency of an activity, we use times.
• Answer: A. times

"Don't ever think gardening is a piece of ... . You must spend a lot of time taking care of your plants."

• The phrase "a piece of cake" is an idiom meaning something is very easy. The sentence is saying the opposite, so work is the correct choice.
• Answer: D. work

"It's ... for a boy to have a hobby of playing dolls."

• While it's not very common, it's not impossible. So, unusual is the best fit.
• Answer: D. unusual

"Jacob is a great artist. He is able to ... in both wood and stone."

• An artist creates or works with materials. So, work is the most suitable option.
• Answer: A. work