Where is the nodal plane of the $\pi$-bond in ethene located?

Nodal planes of $\pi$-bond$(s)$ in $CH_2=C=C=CH_2$ are located in

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

Given below are two statements :
Statement $(I)$ : The oxidation state of an element in a particular compound is the charge acquired by its atom on the basis of electron gain enthalpy consideration from other atoms in the molecule.
Statement $(II)$ : $p\pi-p\pi$ bond formation is more prevalent in second period elements over other periods.
In the light of the above statements,choose the most appropriate answer from the options given below :

Explain the characteristics of $\pi$ bonds. Or,give the requirements for the formation of $\pi$ bonds and explain the active centers.

Why does the type of overlap shown in the following figure not result in bond formation? Explain.