The correct answer is option B, mineral composition
Gneiss is made up of medium to coarse grains and is a semischistose metamorphic rock. Its consists of quartz and feldspar, biotite, hornblende, garnet or graphite. Being formed under high temperature and pressure, gneiss can only be weathered through chemical processes. The quick chemical weathering usually happens when the grains are small in size but in case of gneiss grains being large in size are difficult to be weathered.
