7. Esta is used for talking about the location of one thing and estan is used for more than one. They are both used when talking about whereabouts but about a different amount of things. Answer is A
8. Likely D using process of elimination. Only one that really makes sense.
9. May be incorrect, but I would say C makes the most sense in this context.
Answer:
Él <u>condujo</u> un tanque en el ejército
Explanation:
I hope this helps!!