Which two types of eggs are known to have a firm yolk after cooking?

The choice indicating that over well and over hard eggs have a firm yolk after cooking is accurate. Both cooking methods involve fully cooking the yolk, eliminating the runny texture typically associated with styles such as sunny-side up or over easy.

When eggs are cooked over well or over hard, they are flipped during the cooking process, allowing the yolk to firm up completely. This results in a yolk that is solid and not at all runny, which is ideal for certain dishes or personal preferences where a firmer texture is desired.

In contrast, options involving over easy or sunny-side up styles typically leave the yolk runny, as these methods either cook the yolk lightly or not at all. Therefore, those methods wouldn't achieve the same firm yolk consistency that is characteristic of over well or over hard eggs.