Answer: A. 1/9
Explanation:
to find what fraction of all your books is historical fiction, you would multiply how the fraction of all your books that are fiction by the fraction of fictional books that are historical fiction.
this gives you 2/3 times 1/6.
from there you simply multiply the numerators (2x1=2)
and the denominators (3x6=18)
leaving you with 2/18
but that can be simplified, giving you the final answer of 1/9