[A] : Nuclear membrane of karyotheca forms an envelope-like structure called nuclear envelope around the nuclear contents .
[R] : Each membrane is about 75-90 Å thick and lipoproteinous in nature .

Options

A. 1. If both A and R are true and R is the correct explanation of A
B. 2.If both A and R are true but R is not the correct explanation of A
C. 3 If A is true and R is false
D. 4. If both A and R are false