Several peripheral membrane proteins are tethered to the membranes by covalent linkages with the membrane lipids, .
Example is the one involving phosphotidyl inositol. The fatty acid groups of phosphotidyl inositol are firmly inserted into the lipid membrane thus anchoring the protein.
Membrane proteins have hydrophobic regions that passes through the membrane and interact with the hydrophobic tails of the lipid molecules in the core of the bilayer, since the lipids are inserted into the hydrophobic core, the proteins are firmly anchored.
The correct answer is option - C.
Integral proteins are integrated proteins that are extended into the cytoplasm from the outer side of the cell. As it is known bilipid layer is fluid in nature it move around the cell layer.
These are the proteins also known as intrinsic proteins that contain parts with the side chains that are hydrophobic in nature. These are tightly located or packed between the hydrophobic amino acids and the membrane due to hydrophobic effects.
Thus, the correct answer is - option C.