26. Sheet silicates include a quartz and feldspar b. pyroxene and amphibole c. micas and clays d. diamond and graphite e. galena and sphalerite

The correct option is: C. micas and clays

Explanation:

Phyllosilicates, also known as the sheet silicates, are the important type of silicate minerals that are hydrated because of the presence of water molecules or hydroxyl groups.

The phyllosilicates include the following four groups: serpentine subgroup, clay minerals group, mica group, and the chlorite group.

Therefore, the Sheet silicates include micas and clays.