Select correct statement(s) regarding $\sigma$ and $\mathrm{\pi }$-bonds:

The line connecting the nuclei of $\mathrm{\sigma }-$bond atoms is where the $\mathrm{\sigma }-$bond is located because it is always the first bond to form between two atoms.

No electron is directly involved in the$\mathrm{\pi }-$ bonding axis in $\mathrm{\pi }-$bonding, hence the electron cloud is located on either side of the line connecting the connected atoms' nuclei.

The energy gap between the 2p and 3d orbitals makes them larger than the 2p and 3p in $\mathrm{\pi }-$bonding.

Although sigma bond is the first $\mathrm{\sigma }-$bond to form between two atoms, bond also exists. Thus, the sigma bond alone determines the covalent $\mathrm{\pi }-$bond's primary effect.