Which model shows two equal expressions when c = 5?

c + 1 = 1 + 1 + 1 + 1 + 1 + 1

c + c = 1 + 1 + 1 + 1 + 1 + 1

c + c + c + c + c = 1 + 1 + 1 + 1 + 1

c + c + c + c + c = 1