Answer:
its asking what would you do with a million dollars but ill help you with a few sentences.
si tuviera un millon de dolares lo primero que haria seria donar una pequena porcion a casa hogares al igual que centros de personas nesecitadas. luego compraria una casa para que mi familia y yo vivamos mas comodos. tambien invertiria en algun negocio para que asi en el futuro pueda tener un modo de ingresos.
Explanation:
B) they shake each other's hand
The verb in this sentence,"se dan", comes from "darse", which is a reciprocal verb (verbo recíproco) and these verbs always talk about something that the speakers are mutually doing, so the other options wouldn't be correct because: 1) They aren't referring to the 3rd person of plural, 2) They aren't doing a reciprocated action.
Hope this helped you :)