The Binding Immunoglobulin Protein (BiP) is a molecular chaperone that is essential for the translocation of secreted peptides into the lumen of the ER. Because it is a chaperone, it is important for

 Protein folding and oligomerization

Explanation:

Binding immunoglobulin protein (BiP) is a vital protein present in humans essential for the translocation of secreted peptides.

BiP is  a molecular chaperone which is present in lumen of ER (endoplasmic reticulum) which binds to the new protein and then translocat into the ER. The protein in ER is maintained under subsequent condition and important for protein folding and oligomerization (conversion of a  monomer or group of monomer into an oligomer).

Several other functions of BiP are:

Hence,  BiP is a chaperone, it is important for protein folding and oligomerization.

the correct answer is option d.

an appositive is a noun, noun phrase or noun clause which follows another noun or noun phrase in order to describe it or name it another way. they are usually used between commas, brackets or dashes.

the example sentence with the correct use of commas is the following:

her uncle, the man over there in the red shirt, owns the hardware store in town.