Step 1: Recall the essential components of primary health care.
The Alma-Ata Declaration (1978) lists eight essential elements of primary health care, often remembered as ELEMENTS: Education about health, Locally endemic disease control, Expanded programme on immunization, Maternal and child health including family planning, Essential drugs provision, Nutrition, Treatment of common diseases and injuries, and Safe water and sanitation.
Step 2: Match the options.
Provision of essential drugs is one of the eight elements. Component, so not the answer.
Immunization against major infectious diseases is one of the eight elements. Component.
Health education is the first listed element. Component.
Step 3: Identify the exception.
Cost effectiveness is a desirable principle of how services should be delivered, but it is not one of the eight essential components of primary health care. So it is the correct answer to the "not a component" question.
Answer: Option B.