Question

when an oil gland gets infected, a(n) is formed. pimple ingrown hair hangnail cavity

Explanation:

When an oil - gland (sebaceous gland) gets infected, a pimple is formed. An ingrown hair occurs when hair grows back into the skin. A hangnail is a small, torn piece of skin next to a fingernail or toenail. A cavity is related to teeth decay and not to oil - gland infections.

Answer:

pimple