The main purpose of white blood corpuscles, also known as white blood cells, is to combat infection. White blood cells are an essential part of the immune system and play a crucial role in defending the body against harmful pathogens such as bacteria, viruses, and fungi.

Option 1 - To carry nutrients: This is incorrect. While white blood cells may require some nutrients for their own functioning, their primary function is not related to carrying nutrients throughout the body.

Option 2 - To combat infection: This is the correct answer. White blood cells are responsible for identifying, attacking, and destroying pathogens within the body, helping to prevent and fight off infections.

Option 3 - To carry oxygen: This is incorrect. The transportation of oxygen is primarily performed by red blood cells, not white blood cells.

Option 4 - To give strength: This is incorrect. White blood cells do not provide strength to the body. Strength is primarily attributed to muscles and the skeletal system.

In conclusion, white blood cells are primarily responsible for combating infection and defending the body against harmful pathogens.