Step 1: HT exists to top up estrogen, so its proper indications are the symptoms produced by estrogen withdrawal.
Step 2: Hot flashes are the prototype vasomotor symptom of low estrogen, along with sleep disturbance and vaginal dryness, and HT is licensed to relieve them and to guard against osteoporosis.
Step 3: The remaining options are the opposite of indications: breast cancer is a contraindication, endometriosis is estrogen-fuelled and would worsen, and abnormal uterine bleeding needs work-up first. Only hot flashes qualify.
\[\boxed{\text{Hot flashes}}\]