There are 1000 mL in a Liter.
0.298 mL * 1 L/1000 mL = 0.000298 L
That makes the answer D
You could put in your calculator like this (if that is the problem)
0.298
÷
1000
=
0.000298
I have two calculators. One registers that as the answer and the other one changes into scientific notation
2.98 * 10^-4.
10^-4 requires 3 zeros after the decimal to get rid of 10^-4
0.000298 get's rid of the 10^-4 if that is what your calculator gives you.