I am HORRIBLE at chemistry, Can somebody help me out with this question please.
Carbonic acid (H2CO3) forms when carbon dioxide (CO2) dissolves in water according to this equation:

CO2 + H2O→H2CO3

How many moles of CO2 must dissolve in an excess of water to produce 4 moles of H2CO3 ?
A. 1 mol
B. 2 mol
C. 3 mol
D. 4 mol