If firms in the toothpaste industry have the following market shares, which market structure would best describe the industry?

Market share : (% of market)
Toothpaste : 18.7
Dentipaste : 14.3
Shinibright : 11.6
I can't believe its not toothpaste : 9.4
Brighter than white : 8.8
Pastystuff : 7.4
Others : 29.8

a)Perfect competition
b)Monopolistic competition
c)Oligopoly
d)Monopoly