Assume That Var(u_i|X_i)= ?₀+?₁ $x _ { i } ^ { 2 }$

Multiple Choice

Assume that var(u_i|X_i) = ?₀+?₁ $x _ { i } ^ { 2 }$ One way to estimate ?₀ and ?₁ consistently is to regress

A) $\hat {\mathrm { u }}$ _i on $x _ { i } ^ { 2 }$ using OLS
B) $\hat { u } _ { i } ^ { 2 }$ on $x _ { i } ^ { 2 }$ using OLS
C) $\hat { u } _ { i } ^ { 2 }$ on $\sqrt { x }$ _iusing OLS
D) $\hat { u } _ { i } ^ { 2 }$ on $x _ { i } ^ { 2 }$ using OLS but suppressing the constant ("restricted least squares")