To find out how many milliliters are in 1 gallon, we can start by determining how many quarts are in a gallon and then convert quarts to milliliters.
1 gallon = 4 quarts
Since 1 quart = 946.35 milliliters, we can calculate the number of milliliters in 1 gallon:
\[ \text{Milliliters in 1 gallon} = 4 , \text{quarts} \times 946.35 , \text{mL/quart} \]
Calculating this:
\[ 4 \times 946.35 = 3785.4 , \text{mL} \]
Therefore, the answer rounded to the nearest tenth is:
A. 3785.4 mL