Final answer:
The statement C) x and y are boolean variables is correct because boolean variables represent truth values in programming. The discussion about linear equations relates to determining which equations are of the form y = mx + b; all given options (A, B, and C) meet this criterion.
Step-by-step explanation:
The correct answer to the student's question is C) x and y are boolean variables. In programming, particularly in the context of languages like Java or Python, boolean variables are used to represent truth values, with possible values of true or false. This is unlike other variable types such as real numbers or strings, which represent numerical values or sequences of characters, respectively. Functions, as mentioned in option D, are blocks of code designed to perform a particular task or calculation, so they are not variable types.
Examples of Linear Equations
As for the topic of linear equations, which is part of the Practice Test 4, linear equations are of the form y = mx + b, where 'm' is the slope and 'b' is the y-intercept. Therefore, the equations listed in options A, B, and C of the example question are all linear equations since they can be written in the form y = mx + b.