Assertion: After 24 hours, toddy becomes unpalatable.
Reason: The fermentation of toddy is continued by naturally occurring yeasts.

Both Assertion (A) and Reason (R) are correct and R is the correct explanation of A.

Toddy is a traditional drink of some parts of South India which is made by fermentation of sap of palms. Toddy left for few hours undergoes fermentation with the help of naturally occurring yeast to form beverage containing about 6% alcohol. But after about 24 hours, toddy becomes unpalatable because fermentation is carried on. At this time, it can be used for production of vinegar.