Eighty rupees refers to one amount of money, not separate units.
When money is spoken of as a sum/amount, it is treated as singular.
Therefore, we use the singular verb “is.”
❌ are – used when rupees are counted individually
❌ has / have – not suitable linking verbs here
📌 Rule to remember:
A sum of money → singular verb
✔ So, the correct answer is (A) is.