​Find, if​ possible, the number of elements in sets​ A, B, and C using the given information on the right. Select the correct choice below and fill in any answer boxes in your choice.
A.
​n(A)=nothing
​n(B)=nothing
​n(C)=nothing
B.
It is not possible to find the number of elements in sets​ A, B, and C.
nA∩B=5​, nA∩B∩C=2​, nB∩C=7​, n(B−A)=9​, nB∪C=26​, nA∩C=8​,
nA∪B∪C=31.