The correct option is C 6x + 7y + 3 - 5x + 2y
If an expression has at least one algebraic term, then the expression is called an algebraic expression.
(a) (17 - 6) + 4 = 11 + 4 = 15, it is a numerical expression.
(b) 3x + 6x + 7 - 2 - 9x = 9x + 5 - 9x = 5, it is also a numerical expression.
(c) 6x + 7y + 3 - 5x + 2y = x + 9y + 3, it is an algebraic expression.
(d) (4 - 7) + 9 = 6, it is a numerical expression.