Question

linear pairs and vertical angles
which are vertical angles?
∠afe and ∠bfd
∠bfc and ∠dfe
∠afe and ∠cfd
∠bfc and ∠efa

Explanation:

Vertical angles are formed by two intersecting lines and are opposite each other. For ∠AFE and ∠BFD, they are opposite when lines AB and ED intersect at F, so they are vertical angles. Other options don't meet the vertical angle definition (opposite, formed by intersecting lines).

Answer:

∠AFE and ∠BFD