conditional if or lookup

[Redi]

HI all,
i posted another one like this but i can't seem to find it here in the
group.
I need your help with a formula that would be on column d. if b1=b2
then give me the value in column a with highest number between c1:c2.
if b1 does not equal b2, then give me the value of a1. if
b8=b9=b10=b11, then give me the coresponding column a value with
highest in c8:c11. or another way of looking at is: if column b has
two (or more) numbers of the same, then give me the coresponding
column a value which has the highest number in c.

Column a.......column b........column c
red ...............1......... 1
blue .......... 2........ 4
green .......... 3........ 1
purple ......... 4.......... 1
black ......... 4......... 10
orange ......... 5........... 1
pink ......... 6........... 1
gray ...... 7.......... 7
white ....... 7.......... 1
brown ........ 7......... 5
gold ......... 7.......... 1

thanks in advance.