Answer is A) Al4C3 + 3H2O -> CH4 + 4Al(OH)3
One the left side there are 3 carbon atoms, or moles of carbon, and on the write side there is only one.
In order to solve these problems, count the number of atoms on each side and make sure that for each element, the number of atoms are equal.
For example, for the last problem, we have 1 zinc atom on each sidde, two hydrogen atoms, and two chlorine atoms.