Well, someone has to look daft and guess something - so coconut. Only because coconut water tastes something like bitter water.
Except my one of cacao says it's used to make chocolate which comes from an old Aztec word meaning "dirty water", I was quite excited when I saw that, but I was wrong!
Partially right Dave - the Aztec word is xocolātl, from which we get chocolate, was their name for a beverage brewed from the seed of the cacao tree, and actually means bitter water as the seed is very bitter. The fruit in question is the black sapote, known as the chocolate pudding fruit because of its resemblance to chocolate. I'll be gracious and let you have that one - over to you.
This should be pretty easy: Can you name the first album by a British artist to enter the American billboard hot 100 at number 1?