Which type of bond is formed by the linear overlap of two hybrid orbitals,each containing one electron,associated with two different atoms?

If the internuclear axis is the $z$-axis,then in which of the following cases are $\sigma$ and $\pi$ bonds not possible?

Which of the following overlaps is incorrect (assuming $Z$-axis is the internuclear axis)?
$(A)$ $2p_y + 2p_y \to \pi$-bond formation
$(B)$ $2p_x + 2p_x \to \sigma$-bond formation
$(C)$ $3d_{xy} + 3d_{xy} \to \pi$-bond formation
$(D)$ $2s + 2p_y \to \pi$-bond formation
$(E)$ $3d_{xy} + 3d_{xy} \to \delta$-bond formation
$(F)$ $2p_z + 2p_z \to \sigma$-bond formation

Which overlap results in the formation of the strongest bond?

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

Which of the following represents the most effective overlapping?