Which of the following molecules has two $\sigma$ and two $\pi$ bonds?

How many $\sigma$ and $\pi$ bonds are present in each of the following molecules?
$(a)$ $HC \equiv C-CH=CH-CH_3$
$(b)$ $CH_2=C=CH-CH_3$

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

$A$ molecule $(X)$ has $(i)$ four sigma bonds formed by the overlap of $sp^2$ and $s$ orbitals,(ii) one sigma bond formed by $sp^2$ and $sp^2$ orbitals,and (iii) one $\pi$ bond formed by $p_z$ and $p_z$ orbitals. Which of the following is $X$?

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

The $F_2$ molecule is formed by which of the following?