Where is the action or linking verb in “her sister are the loudest sleepers in the house”

Which of these sentences is the correct one?

What is central purpose of the letter

(01.03 mc) what does the conversation between marcus and his father reveal about their characters? a marcus doesn't agree with the regulations put in place, but his father does. b marcus's father doesn't agree with the regulations put in place, but marcus does. c marcus's father thinks the regulations provide security, and so does marcus. d marcus wants stricter regulations to be put in place, and his father agrees.