The strength of bonds formed by $2s-2s$,$2p-2p$ and $2p-2s$ overlap has the order

How many $\sigma$ and $\pi$ bonds are there in the molecule of tetracyanoethylene $(CN)_2C=C(CN)_2$?

Which of the following molecules possesses a bond formed by $sp^2-sp$ orbital overlap?

Assuming the bond direction is along the $z$-axis,which of the following overlaps of atomic orbitals of two atoms $(A)$ and $(B)$ will result in bonding?
$I$. $s$-orbital of $A$ and $p_x$-orbital of $B$
$II$. $s$-orbital of $A$ and $p_z$-orbital of $B$
$III$. $p_y$-orbital of $A$ and $p_z$-orbital of $B$
$IV$. $s$-orbital of both $(A)$ and $(B)$

Which of the following statements is $NOT$ true regarding the sigma and pi bonds formed between two carbon atoms?

State the resemblance and difference between $\sigma$ ($\sigma$) and $\pi$ ($\pi$) bonds.