Choose the correct statement on the estimation results and/or hypothesis testing.

We use the dataset "MASchools" in the package "AER" like we did in R-Exercise 2. The dataset contains information on test performance, school characteristics and student demographic backgrounds for school districts in Massachusetts (MA). In this exercise, we shall use R-functions in the packages "estimate" and "AER" (or "car"). We wish to learn the effect of student-teacher ratio (STR) on the 4th grade score (TestScore), which is defined as the sum of math, English, and science. In order to control for omitted variable bias, we shall include a few other additional variables and consider various functional forms. For all estimation exercises here the type of standard error should be "HC1" or equivalently "stata".QUESTION 7 Estimate the population regression model, TestScore; = Bo+ B1STR; + B2English; + B3(STR; x English;) + u; where English, is the percentage of English Learners in school district . Using the estimation results we wish to test the hypothesis below. Ho : The effect on test score of class size does NOT depend on the percentage of English learners. Choose the correct statement on the estimation results and/or hypothesis testing. O a. Since the OLS estimate is not significant at the 5% level, we should reject Ho. b. The sample correlation coefficient between English and the interaction term (STR x English) is greater than 0.98. Thus, we should drop English or (STR x English) to avoid perfect multicollinearity. O C. The p-value for testing Ho is between 0.01 and 0.05. O d. The heteroskedasticity F-statistic for testing His greater than the critical value for the 10% significance level. e. We cannot test Ho because we do not include in the model the dummy variable for school districtis with a high proportion of English learners