The vesicles present in endoplasmic reticulum fuse with:
Primary lysosome
Plasma Membrane
Golgi body’s maturing face
Golgi body’s forming face
Option 4 is correct because the vesicles present in the endoplasmic reticulum fuse with the forming face or cis face of the Golgi body and start moving towards the maturing face of the Golgi body. Therefore, the Golgi apparatus is closely associated with the endoplasmic reticulum as proteins that are synthesized by ribosomes undergo further modifications in the cisternae of the Golgi apparatus.
Explanation for the incorrect options :
Option 1 is incorrect because the vesicles present in the ER do not fuse with primary lysosomes. Lysosomes are vesicular organelles that are formed by the packaging of the Golgi apparatus.
Option 2 is incorrect because the Plasma membrane doesn’t get fused with the vesicles present at the endoplasmic reticulum.
Option 3 is incorrect because the vesicles situated at the ER do not fuse with the maturing face or concave trans. Though, the maturing and forming face are interconnected but are very different.