Density problems (work check)

Here's a question I was working on:

A crystal of sulfur has a density of 1.94 g/cc.

(a) What is the mass (in grams) of a sulfur crystal with a volume of 2.534 cm3?

(b) What is the density of sulfur in kg/m3?

(c) What is the volume (in mL) of a sulfur crystal that weighs 9800 mg?

Here is the solutions I've arrived at:

(a) Well we know $\displaystyle D = M / V$ thus rearrange as $\displaystyle M = D * V$ to obtain the value of $\displaystyle 4.91596g$ which I rounded to $\displaystyle 4.92g$ as taking into account significant digits.

Correct or incorrect?

(b) I know $\displaystyle D = 1.94 g/cc$ thus I can write $\displaystyle 1.94 g/cc / 1000 = 0.00194 kg/m3$

I'm not so sure about the sig figs on that final answer there, or if it's even the correct conversion at all?

(c) I rearrange as such: $\displaystyle V = M / D$ and plugged in $\displaystyle 9800mg / 1.94g per cc = 5051.5mL$

Is this correct?

If you could help me with the mistakes I made and offer advice, etc. that would be appreciated. Thanks a lot for reading. :)