Someone please help thank you

Which of the following sentences below uses the simplest and clearest language? a. library cards are not too hard to get, but they aren't too easy to get either. b. some libraries have a lot of rules to follow for filling out the forms. c. library cards make it possible to read books all year long. d. once you get the application, you can figure it out.

"dogs make wonderful pets because they us stay happy and healthy"the topic sentence is "dogs make wonderful pets" i need writing a sentence that is unrelated to the topic and can be eliminated.

Dogs make wonderful pets because they us stay happy and healthy. the topic sentence is "dogs make wonderful pets." , is this correct? i keep doubting myself.