Answer:
The answer is A. It is a molecular formula.
Explanation:
A molecular formula express the real number of atoms that form a molecula. In the problem you can see this compound has two carbon atoms, six hydrogen atoms and one oxygen atom.
It is not an ionic compound because between different atoms you don't have an electronegative difference greater than 1,7 (That's the convention to define a compound as ionic).
Formula unit is a definition for solids but C₂H₆O is a little molecule without electrostatic interactions (because is not an ionic compound).
And last, the formula represents two carbon atoms, six hydrogen atoms and one oxygen atom. So, d option is clearly false.
I hope it helps!
