The correct answer is: B. relevant range
A relevant range is the range of values for an independent variable over which the relationship between the independent and dependent variables is considered linear.
In specification analysis, assumptions related to linearity states that the relationship between the independent and dependent variables must be linear within the relevant range. This is because if the relationship is not linear, then the results of the analysis will be inaccurate.
Option A is incorrect because an irrelevant range is a range of values for an independent variable over which the relationship between the independent and dependent variables is not considered linear.
Option C is incorrect because a significant range is a range of values for an independent variable over which the relationship between the independent and dependent variables is considered to be statistically significant.
Option D is incorrect because an insignificant range is a range of values for an independent variable over which the relationship between the independent and dependent variables is considered to be statistically insignificant.