The participle is "digging." Most participles end in -ing. It modifies "man", describing what the man is doing.
The word "expose" comes from the Latin word "expositus" meaning put or set out and from Old French word "poser" meaning to place. Therefore the exact meaning of the word expose is to put out. The correct answer would be option A.
I believe that the answer could be absolutely anything, if so then “extreme” and words similar to it could fit there.
“A flash of extreme joy appeared upon the woman’s face.”
