To determine the weight of equity (We) in the WACC calculation, we use the formula:

$We = 1 - Wd$ where $Wd$ is the weight of debt, calculated as:

$Wd = \frac{D/E}{1 + D/E}$

Given the debt-to-equity ratio (D/E) of 0.5:

$Wd = \frac{0.5}{1 + 0.5} = 0.333$

Thus, the weight of equity is:

$We = 1 - 0.333 = 0.667 \approx 0.67$

Option A (0.33) is incorrect as it represents the weight of debt, not equity. Option B (0.50) is incorrect as it reflects the debt-to-equity ratio, not the weight of equity.