Practice using the mean value theorem.

Problem

Let f, left parenthesis, x, right parenthesis, equals, x, start superscript, 3, end superscript, plus, 6, x, start superscript, 2, end superscript, plus, 6, x and let c be the number that satisfies the Mean Value Theorem for f on the interval open bracket, minus, 6, comma, 0, close bracket.
What is c ?
Please choose from one of the following options.