Bacterial and fungal degradation come under microbial degradation or biodegradation.
Plastic should be treated before subjecting to biodegradation. It should be broken down into bits and then treated with UV light. UV light will convert plastic into toxic bisphenol A.
This treated plastic is subjected to decomposition. Certain workers have given heat treatment also, before carrying out biodegradation.
In the end, bacterial treatment is given. Studies have proved that many strains of Pseudomonas are effective in degrading plastic. There are many fungal strains also which have proved to be effective.
So, your answer will be “a”.