Answer:
Cash memo
Step-by-step explanation:
A cash memo is a docent that evidences transaction that occurred between a buyer and seller when cash was used to make a purchase.
A seller prepares a cash memo and gives to the buyer as a proof that the transaction occurred.
In this scenario where Ravi purchased two kilograms of sweets from Nandan Sweets that made his wife fall sick and she was hospitalized. If he wants to file a case in the consumer forum, he will need proof.
A cash memo would have been used