the size of molecule which can pass through plasma membrane

a) 4-15 angstrom

b) 25-80 angstrom

c) 8-10 angstrom

d) 10-35 angstrom

The correct option is (a).
The size of plasma membrane is between 30 - 100 angstrom. Therefore, molecule of size 4-15 angstrom can enter through plasma membrane.