**Core Concept**
The extended sickness benefit is a provision under the Employees' State Insurance (ESI) scheme in India, designed to provide financial support to insured employees who are unable to work due to sickness or injury. This benefit is intended to supplement the employee's income during their recovery period.

**Why the Correct Answer is Right**
The extended sickness benefit is granted for a maximum period of 309 days, which is the duration of the extended sickness benefit under the ESI scheme. This period is calculated from the date of commencement of the sickness or injury. During this period, the employee receives 70% of their average daily wages as the extended sickness benefit. The payment is made directly to the employee's bank account, eliminating the need for physical cash transactions.

**Why Each Wrong Option is Incorrect**
**Option B:** 409 days is not the correct duration for the extended sickness benefit. This option is incorrect as it exceeds the actual duration of the benefit.
**Option C:** 365 days is the duration of a standard year, but it is not the correct answer for the extended sickness benefit. This option is incorrect as it does not account for the actual duration of the benefit.
**Option D:** 490 days is not a valid option for the extended sickness benefit. This option is incorrect as it is not a recognized duration for the benefit.

**Clinical Pearl / High-Yield Fact**
It's essential to note that the extended sickness benefit is subject to certain conditions and eligibility criteria, such as the employee's contribution to the ESI fund, the nature of the sickness or injury, and the availability of medical certificates. Insured employees must submit medical certificates and other supporting documents to claim the extended sickness benefit.

✓ Correct Answer: A. 309 days