Answer:
The correct formula for Jeff to calculate the monthly cost of raw materials in cell E2 and copy to all rows below is option B:
\[ \text{B.} \quad =\$A2 \times D2 \]
This formula multiplies the fixed cost of raw materials in cell A2 by the quantity (number of units) in each corresponding row in column D. The dollar signs (\$) before A and D indicate that these references should remain fixed when copied to other cells, ensuring that Jeff is always multiplying by the fixed cost in A2 and the quantity in the respective row in column D.