Which phrase best completes this sentence?

Luis: Nous sommes allés au centre commercial pour acheter un ordinateur et nous avec ma carte de crédit.

A.
sommes venues
B.
avons acheté
C.
sommes allées
D.
avons payé

Your new boss just entered your office, he says "bonjour monsieur, comment allez-vous? ". how would you answer his question? by saying “ça va. et toi? ” by shake his hand and saying ”salut. et vous? ” by saying “bonjour. et toi? ” and shaking his hand. by shaking his hand and saying ”bonjour. bien et vous? ”

Any french speakers? could someone check if my grammar is correct? my text: ma visite au zoo se passe bien. c’est très intéressant. ii y a les ours, les éléphants, les lions, les singes, les tigres, et les canards. les ours dorment. les singes sauter beaucoup. les tigres courent vite. les marchent canards.what i was it to say in english: my visit to the zoo is going good. it is very interesting. there are bears, elephants, lions, monkeys, tigers, and ducks. the bears sleep. the monkeys jump a lot. the tigers run fast. the ducks walk.

Explain what has to happen when you use être instead of avoir for the formation of the passé composé? il an english explanation with steps if possible