My sister,an inexperienced rider,was found sitting on the bicycle _____to balance it.

My sister,an inexperienced rider,was found sitting on the bicycle _____to balance it.
A.having tried B.trying C.to try D.tried
为什么选B?was found sitting on the bicycle 不就是相当于 …found her sitting on the bicycle 不已经满足了find+宾语+宾语补足语 的
怎么又选个B作宾补?
为什么不能选C