Approach this by ruling out the arable classes first.
Land capability classes I, II, III and IV are all considered fit for cultivation, class I needs almost no special care while II, III and IV need increasing levels of conservation practice, but crops can still be grown on all four. So any option built only from classes I to IV describes cropland, not pasture, and can be dropped.
Once cultivation land is set aside, land that is too steep, too stony, too wet, or too shallow for the plough is left over. This land, classes V, VI and VII, is instead put under grass, trees, or left for wildlife.
Checking the answer choices, only the pair of class V and class VI represents this non-arable, grazing suited land.
\[ oxed{ ext{class V and class VI}} \]