At 25 °C, \({\text{200 c}}{{\text{m}}^{\text{3}}}\) of \({\text{1.0 mol}}\,{\text{d}}{{\text{m}}^{ - 3}}\) nitric acid is added to 5.0 g of magnesium powder. If the experiment is repeated using the same mass of magnesium powder, which conditions will result in the same initial reaction rate?

D