n+1Cn+1=? n∈N
n+1Cn+1=(n+1)!(n+1)!0!=1
Similarly, take each option and simplify them.
nCn=n!n!0!=1
n+2Cn+2=(n+2)!(n+2)!0!=1
n+3Cn+3=(n+3)!(n+3)!0!=1
n−1Cn−1=(n−1)!(n−1)!0!=1
We see all the options having same value.
All A, B, C and D are correct.