Aladin Akyurek wrote...
=INDEX(A2:A100,MATCH(MAX(B2:B100),B2:B100,0))
....

Finds the topmost match. If there were multiple instances of the MAX
value, would any corresponding col A value be equally acceptable? If
so,

=LOOKUP(2,1/(B2:B100=MAX(B2:B100)),A2:A100)

would be a bit more efficient, and would return the bottommost match.