The correct answer is C. linear.
Simple regression is a statistical method that is used to estimate the linear relationship between two variables. The dependent variable is the variable that is being predicted, and the independent variable is the variable that is used to make the prediction.
A linear relationship is a relationship between two variables that can be represented by a straight line. In simple regression, the line is called the regression line. The regression line is used to make predictions about the value of the dependent variable for a given value of the independent variable.
The other options are not correct because they do not represent a linear relationship. A quadratic relationship is a relationship between two variables that can be represented by a parabola. An inverse relationship is a relationship between two variables where the value of one variable decreases as the value of the other variable increases. A reciprocal relationship is a relationship between two variables where the value of one variable is the inverse of the value of the other variable.