What are the postulates of mandeleev in the periodic table

Which material produces static charge when rubbed ?

The answer for #3 is c but i don't know why

The human eye contains a molecule called 11-cis-retinal that changes shape when struck with light of sufficient energy. the change in shape triggers a series of events that results in an electrical signal being sent to the brain that results in vision. the minimum energy required to change the conformation of 11-cis-retinal within the eye is about 164 kj/mol.