Which is the most ideal feed stock for 'coking' process used for the manufacture of petroleum coke?

Answer: Option B

The correct answer is B: Vacuum residue.
Here's why:

Coking is a process that uses heat to break down large, heavy hydrocarbon molecules into smaller, lighter ones and solid carbon (coke).

Vacuum residue is the heaviest fraction remaining after vacuum distillation of crude oil.
It contains the largest and most complex molecules, making it the most suitable feedstock for coking.

Let's look at the other options:

Naphtha, Light gas oil and Diesel are all relatively lighter fractions with smaller molecules.
They do not contain enough of the heavy components required for efficient coke production.
These fractions are generally used as gasoline, diesel fuel, and heating oil.

Therefore, vacuum residue is the most ideal feed for coking because it maximizes coke production.