To convert 6,750 milliliters to liters, you can use the conversion ratio where 1 liter equals 1,000 milliliters.
You can set up the conversion like this:
\[ \text{liters} = \frac{\text{milliliters}}{1,000} \]
Substituting the given value:
\[ \text{liters} = \frac{6,750}{1,000} = 6.75 \]
So the cylinder holds 6.75 liters.
The correct answer is D) 6.75.