How many radial nodes are present in $4s$ and $3s$ orbitals respectively?

The number of radial nodes of $3s$ and $2p$ orbitals are respectively.

The extra stability of half-filled subshells is due to:
$(A)$ Symmetrical distribution of electrons
$(B)$ Smaller coulombic repulsion energy
$(C)$ The presence of electrons with the same spin in non-degenerate orbitals
$(D)$ Larger exchange energy
$(E)$ Relatively smaller shielding of electrons by one another
Identify the correct statements.

$A$ certain orbital has $n = 4$ and $m_{L} = -3$. The number of radial nodes in this orbital is .......... (Round off to the Nearest Integer).

The plots of radial distribution functions for various orbitals of hydrogen atom against $r$ are given below.
The correct plot for $3s$ orbital is

Consider the ground state of chromium atom $(Z=24)$. How many electrons are with Azimuthal quantum number $l=1$ and $l=2$ respectively?