Context: Madelyn leaves some chocolates in her jacket pocket. When she finds the chocolates later, she notices that some of them have melted. She wonders what factors affect how quickly chocolate melts. So, she decides to design an experiment. She has the following supplies available:
one bar of milk chocolate
one bar of dark chocolate
a stove
a pot
Using only these supplies, which question can Madelyn investigate with an experiment?
A. Does milk chocolate or dark chocolate melt faster when heated on the stove?
B. Does milk chocolate melt faster when heated in a microwave or on a stove?
C. Does dark chocolate or white chocolate melt faster when heated on the stove?
From the given choices, choose the correct answer and respond with the letter of that choice.

A