Explanation:

- Correct Answer: Option 2: Goa

- In October 2020, Goa became the first state in India to achieve the goal of providing a tap water connection to every rural household under the Jal Jeevan Mission.

- Option 1: Bihar

- Bihar was not the first state to achieve 100% tap water connections in rural households by October 2020. The state is working towards the goal under the Jal Jeevan Mission but was not the pioneer.

- Option 3: West Bengal

- West Bengal was also not the first to complete the task of providing every rural household with a tap water connection by the specified date.

- Option 4: Sikkim

- Sikkim, similar to Bihar and West Bengal, achieved significant progress in providing tap water connections but was not the first to complete the task by October 2020.

Overall, Goa's achievement was a part of the central government's vision to provide safe and adequate drinking water through individual household tap connections by 2024.