Answer:
d. 0.9 mol
Step-by-step explanation:
On this case we have to start with the formula of acetylene:

Now we can write the chemical reaction of combustion:

The next step is to balance the reaction:

The molar ratio between
and
is 2:4, so:

The molar ratio between
and
is 2:2, so:

The total moles would 0.6 + 0.3=0.9 moles.
I hope it helps!