We have two fractions and you have to multiply numerator per numerator and denominator per denominator...
[tex]\frac{numerator}{deno\min ator}=\frac{9}{10}\cdot\frac{3}{8}=\frac{9\cdot3}{10\cdot8}=\frac{27}{80}[/tex]Now, we need to simplify the result.. we do that probing divide numerator and denominator by the same number, but in this case we don have one for both cases.. then your answer is A