The number of correct statements from the following is ________.
A. For \( 1s \) orbital, the probability density is maximum at the nucleus
B. For \( 2s \) orbital, the probability density first increases to maximum and then decreases sharply to zero
C. Boundary surface diagrams of the orbitals encloses a region of \( 100\% \) probability of finding the electron
D. \( p \) and \( d \)-orbitals have \( 1 \) and \( 2 \) angular nodes respectively
E. Probability density of \( p \)-orbital is zero at the nucleus