Letter b or c? (Did ... see/were)

[Vuser]

7) _______________ (see) you ________ any grizzly bears when you________ (be) in the park last year?

A) Have ... seen/was

B) Did ...see/were

C) Have...seen/were

D) Do...see/have been

[Milanya]

B) Did ...see/were
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con·text - The part of a text or statement that surrounds a particular word or passage and determines its meaning.

[Cerberus™]

As Milanya said, b is correct. The simple past is used here because the sentence is about a situation that happened at a specific time in the past that does not continue up to the present.