@shivam sharma 5
don't miss use the tags.... you can include your requirement either in your question or comment
p = &arr[1] [1] [1]
p holds the address of the element at 1^{th }column of 1^{th }row of 1^{th} 2-D array.
1^{th }2-D matrix is $\begin{pmatrix} 5 &6 \\ 7 &8 \end{pmatrix}$
Then 1^{th} row is [7 8]
Element at 1th colum is 8.
So p holds the address of 8 and *p gives value at that address which is 8.
q holds the base address of the 3-D array type casted to (int *) as q is a pointer to an integer type. The element at the base is 10(i.e. the first element). So *q gives 10.