Which of the following is non negative?	Answers:
A) (c-0.9)(c-1)	B) (c+1)(c-1)	C) (c-0.9)(c-0.9)	D) (c-0.9)(c+0.9)	E) c(c+1)
5-sec approach:   C. (c-0.9)(c-0.9) = (c-0.9)^2. The square of a number is always non-negative.   Answer: (c-0.9)(c-0.9).
<result>C</result>
Which of the following is non negative?