Answer:
Rock B is medium-grained and rock D is fine-grained.
Explanation:
Rock Classification Composition
A Clastic large rounded rock fragments
B Clastic quartz and small rock fragments
C Clastic large angular rock fragments
D Clastic clay
Rocks B and Rock D differs in their grain size in that, Rock B is medium-grained and Rock D is fine-grained.
Clay sized particles are the finest of all grains. They range in size of less than 0.002mm.
According to the udden-wentworth scale, clay clastics are very fined grained and powdery.
The rock B which is a clastic quartz and small rock fragments can be said to be medium grained.
They have size dimension of between which is similar to that of silts or sands.
Since we are dealing with quartz and small rock fragments, they must probably be sands with dimensions 0.06 mm and 2 mm.
