To calculate work done, the correct formula to use is:
\[ \text{Work} = \text{Force} \times \text{Displacement} \times \cos(\theta) \]
where \( \theta \) is the angle between the direction of the force and the direction of the displacement. If the force acts in the same direction as the displacement (\(\theta = 0\)), then \(\cos(0) = 1\), and the formula simplifies to:
\[ \text{Work} = \text{Force} \times \text{Displacement} \]
In this scenario, since the force is given as 30 N and the displacement as 15 m, the correct calculation would be:
\[ \text{Work} = 30, \text{N} \times 15, \text{m} \]
Based on the options provided, the correct choice would be:
The student should multiply the force (30 N) by the displacement (15M).