the to your question is b
Question 1 with 1 blank Omar y Antonio / almorzar / restaurante japonés
Answer 1: Omar y Antonio han almorzado en un restaurante japonés.
Omar and Antonio have had lunch in a Japanese restaurant.
Question 2 with 1 blank usted / no poder / ver la película / porque / no encontrar / el cine
Answer 2: Usted no ha podido ver la película porque no encontró el cine.
You couldn't watch the movie because you didn't find the cinema.
19 is preterite. 20 is imperfect. 21 is conditional.
I think it's 'estarán' meaning 'they will be'