The correct option is C Optical isomerism, Geometrical isomerism
Stereoisomerism is the arrangement of atoms in molecules whose connectivity remains the same but their arrangement in space is different in each isomer. It has two different type configurational and conformational isomerism. Further configurational isomerism can be classified as geometrical and optical isomerism. thus geometrical and optical isomerism are part of stereoisomerism. Hence, correct answer is option (c).