**Core Concept**
The function of a Health Worker Female (HWF) involves providing basic health care services to the community, particularly in rural areas. This includes training and supervision of traditional birth attendants, also known as dais, to ensure safe and hygienic practices during deliveries.

**Why the Correct Answer is Right**
The HWF plays a crucial role in training dais to perform their duties effectively. Training dais enables them to recognize complications during delivery, take necessary precautions, and refer complicated cases to higher centers. This not only improves maternal and infant health outcomes but also reduces the risk of mortality and morbidity associated with unhygienic practices. The HWF also supervises the dais to ensure that they adhere to the recommended protocols and guidelines for safe delivery practices.

**Why Each Wrong Option is Incorrect**
**Option A:** Performing 50% of deliveries is not a specific function of the HWF, although they may be involved in some deliveries. This option is too general and does not accurately reflect the role of the HWF.
**Option C:** Enlisting dais of the subcentre is a responsibility of the ASHA (Accredited Social Health Activist) under the National Rural Health Mission, not the HWF.
**Option D:** Chlorination of water is a function of the sanitation and water supply department, not the HWF.

**Clinical Pearl / High-Yield Fact**
The HWF plays a critical role in bridging the gap between the formal health system and the community, especially in rural areas. They work closely with the dais to ensure that basic health care services are accessible and affordable to the community.

**✓ Correct Answer: B. Trains dais**