Suppose We Omit X₂ from the Following in a Bivariate $\beta$

Multiple Choice

Suppose we omit X₂ from the following in a bivariate model
Y_i = $\beta$ ₀ + $\beta$ ₁X_1i + $\varepsilon$ _i
And suppose X₂ is positively related to X₁ and $\beta$ ₂ is positive, while $\beta$ ₁ is negative. What is the likely effect of omitting X₂ on our estimate of $\beta$ ₁?

A) No effect; $\beta$ ₁ hat will be unbiased.
B) $\beta$ ₁ hat will be more negative than it should be.
C) $\beta$ ₁ hat will be less negative than it should be.
D) $\beta$ ₁ hat will be biased toward zero.