The correct answer is 1/4.
Notice that we have three similar triangles in this figure.
This is the Triangle Midsegment Theorem. Why?
HI is a segment that is the midpoint of AN and AO,
NO is a segment that is the midpoint of AB and AC.
Thus that means that


Notice that we are asked for AH to AC.
So we are looking at the two similar triangles, AHI and ABC.
By definition, their sides form a proportion.
So that means that for some number, k,
k(AH)=AB
k(HI)=BC
k(AI)=AC
Notice that

We also know that

So


So that means Triangle AHI is 1/4 of ABC
Thus, the ratio is 1/4.