True or False:

a) ____ Under the null hypothesis of the Durbin-Wu-Hausman (DWH) test, the difference ^2SLS^OLS can be attributed exclusively to sampling error.

b) ____ Tests of overidentifying restrictions are used to check the assumption of strong correlation between the set of instrumental variables and the endogenous variables when there are more instruments than needed for identification.

c) ____ The RESET test is not designed to detect omitted variables in general or heteroscedasticity.