What is the difference in the place values of the two 3’s in 3938?

The correct option is B

2970

$\begin{array}{cccc}\text{Th}& \text{H}& \text{T}& \text{O}\\ 3& 9& 3& 8\end{array}$

The place values of 3's in the number $\underset{–}{3}9\underset{–}{3}8$ are $3\times 1000=3000$ and $3\times 10=30.$

So, the required difference is 3000 - 30 = 2970.