In the 2SLS estimation, which one is incorrect?
A.
The number of instrumental variables must be larger than or equal to the number of endogenous variables.
B.
Every instrumental variable must be correlated with every endogeneous variable.
C.
The 2SLS estimator is consistent under regularity conditions in Chapter 7, though its asymptotic variance may be larger than the OLS estimator.
D.
must be finite and of full rank to ensure that the 2SLS estimator is well-defined.