**Core Concept**
The Sickness Benefit under the Employees' State Insurance (ESI) Act is a form of social security benefit provided to insured persons who are absent from work due to certified illness or injury. This benefit is designed to provide financial assistance to employees during periods of temporary disability.

**Why the Correct Answer is Right**
The Sickness Benefit under the ESI Act is payable for a maximum of 91 days in a year. This benefit is calculated at a rate of 70% of the average daily wages of the insured person, subject to a maximum amount. The benefit is payable for a continuous period of 91 days in a year, and the insured person is entitled to receive this benefit for the full 91 days only if they are certified to be unfit for work by a medical officer.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not specify the correct number of days for which the Sickness Benefit is payable.
**Option B:** This option is incorrect as it exceeds the maximum number of days for which the Sickness Benefit is payable.
**Option C:** This option is incorrect as it is less than the actual number of days for which the Sickness Benefit is payable.

**Clinical Pearl / High-Yield Fact**
It is essential for medical professionals and insurance administrators to be aware of the specific provisions of the ESI Act, including the duration of Sickness Benefit, to ensure timely and accurate payment of benefits to insured persons.

**Correct Answer: A. 91 days.**