Monica, Phoebe, Rachel, Chandler, Joey, and Ross bid on a much-coveted resource (Marcel the monkey). Monica, Phoebe, Rachel, Chandler, Joey, Ross, and Marcel bid as follows: $9, $72, $81, $36, $96, $18, and $0 respectively. The friends decide that Joey should get Marcel. How much does Joey pay? 
a) $18 
b) $36 
c) $72 
d) $96