1. The problem asks to determine how many terms the expression $xyz$ has and whether Greg's reasoning about the number of terms is correct. 2. Recall that in algebra, a term is a part of an expression separated by plus ($+$) or minus ($-$) signs. Multiplication does not separate terms; it combines factors within a single term. 3. The expression $xyz$ has no plus or minus signs, so it consists of only one term, which is the product of the variables $x$, $y$, and $z$. 4. Greg's reasoning that each variable is a separate term is incorrect because terms are separated by addition or subtraction, not by multiplication. 5. Therefore, the correct answer is: $$\text{C. Greg is not correct. The expression } xyz \text{ has one term, } xyz. \text{ It is the only term because there are no other parts separated by a plus or minus sign.}$$