The correct answer is B. Electricity Bill.
An annuity is a series of equal payments made at regular intervals for a fixed or indefinite period of time. The payments can be made monthly, quarterly, semi-annually, or annually. Annuities are often used to provide retirement income or to fund other long-term goals.
Option A is a case of annuity because it meets the definition of an annuity. The payment of Rs.10,000 is made at regular intervals (every year) for a fixed period of time (one year).
Option B is not a case of annuity because the payment of electricity bill is not made at regular intervals. The amount of the payment may vary depending on the usage of electricity.
Option C is a case of annuity because the car payments are made at regular intervals (monthly) for a fixed period of time (the term of the loan).
Option D is a case of annuity because the mortgage payments are made at regular intervals (monthly) for a fixed period of time (the term of the mortgage).