In English "cocoa" (какао) and "chocolate" (шоколад) are in principle quite distinct but in practice extremely close and often interchangeable. This is somewhat context dependent, though in this case the sentence is so simple that little context is available. One might consider both chocolate and cocoa as acceptable translations. Just a thought :)
The word cocoa by itself can mean the drink hot cocoa, or pretty much anything derived from cocoa beans (cocoa powder, cocoa butter, etc). The word chocolate usually only refers to the solid food and hot chocolate means the drink.
BTW, also in English we occasionally use cacao instead of cocoa, e.g. the nibs are commonly called cacao nibs though cocoa nibs is also used.
I hadn't realized that какао was used only for drinks, since in English it can mean so many things. In that case, chocolate is NOT an acceptable answer, though probably hot chocolate should be. :)
Both are correct. Vashi is when you are speaking to a group of people like a waitress serving water to a table full of people, they usually say "here is your water" but you can also say here is your water to just one person.
Твоё - singular
Baше - plural
Note: Ваше can also be used with a single person whom you don't know well and/ or show respect. This version is formal.