Give `IUPAC` name of the following using `E//Z` and `R//S` designations.
`a.` , `b.`
`c.`

Explanation

`a.` The priority order `:`
`(CH-=underset(oa)C-)gt((CH_(3))_(3)C-)gt(CH_(2)=CH-)gt [(CH_(3))_(2)CH-]`
The lowest priority is on the dotted line.

Clockwise direction `=R` absolute configuration at `4-C` , so written as `(4R)`.

Two higher priority groups on opposite sides, so `(E)`. `(2E,4R)-3-`Methyl `-4-(1-` methyl ethl`) -4-(1,1-`dimethyl ethyl `)-hex-2-`en`-5-`yne.
`b.`
The priority order `:`

As anti `-` clockwise , so the aboslute configuration of `C-4` is written as `(4S)`.

Two highes priority groups around the double bond on the same side, so it is `Z`.
`c.`
Two highest priority groups on the same side, so it is `Z`.

The priority for the absolute configuration

The lowest priority is on the dotted line.

The clockwise , absolute configuration at `C-3` is `R`.