The rank of the matrix $$\left[ {\matrix{ 0 & 0 & { - 3} \cr 9 & 3 & 5 \cr 3 & 1 & 1 \cr } } \right]$$ is

The number of distinct simple graph with upto three nodes is

If A and B are real symmetric matrices of size n x n. Then, which one of the following is true?

The number of substrings (of all length inclusive) that can be formed from a character string of length $$n$$ is