Which of the following statements is correct? OLS is bias and inconsistent when applied to a structural equation in a simultaneous a. equations system. Ob. 2SLS can be applied to SEMs equations, to solve the problem of endogenous `explanatory variables, for each equation that is identified. It is the presence of an exogenous variable in one of the two-equation SEM (with a Oc. nonzero coefficient), not present in the other equation of the SEM, which makes the later equation identified. Od. All of the above. QUESTION 10 Consider the following agricultural labor supply: As = a1 Wag + B1Wmanuf + 41 (1), where he denotes the annual labor hours supplied by workers in agriculture, Wag denotes the average hourly wage offered to workers in agriculture and Wmanuf denotes the average hourly wage offered to workers in manufacturing, all measured at the county level. Further consider the following agricultural labor demand: /d = a2wag + B2land + U2 (2), where ha is hours demanded and /and is agricultural land area, all measured at the county level. Which of the following statements is correct? Oa. Equation (1) is an example of a reduced form equation. Ob. Wmanuf is called the observed demand shifter. Oc. When we combine the equilibrium condition, As = ha, with equations (1) and (2), we get a suitable simultaneous equations model (SEM). Od. All of the above