Which of the following would result in the formation of the strongest $\pi-$ bond if the molecular axis is the $x-$axis?

What is the total number of sigma $(\sigma)$ and pi $(\pi)$ bonds in the following molecules?
$(a)$ $C_{2}H_{2}$
$(b)$ $C_{2}H_{4}$

The number of sigma $(\sigma)$ and pi $(\pi)$ bonds present in benzene respectively are:

Match the orbital overlap figures shown in List-$I$ with the description given in List-$II$ and select the correct answer using the code given below the lists.
List-$I$:
$P$. Two $d$-orbitals overlapping axially with same phase.
$Q$. $A$ $p$-orbital and a $d$-orbital overlapping laterally with same phase.
$R$. $A$ $p$-orbital and a $d$-orbital overlapping laterally with opposite phase.
$S$. Two $d$-orbitals overlapping axially with opposite phase.
List-$II$:
$1$. $p-d$ $\pi$ antibonding
$2$. $d-d$ $\sigma$ bonding
$3$. $p-d$ $\pi$ bonding
$4$. $d-d$ $\sigma$ antibonding
Codes: $P \quad Q \quad R \quad S$

In a $\sigma$ bond,

In $N_2$ molecule,the atoms are bonded by