Receptors for sperm binding in mammals are present on :

The zona pellucida is a glycoprotein-rich extracellular matrix that surrounds the oocyte and early embryo in mammals.

During fertilization, sperm must first recognize and bind to specific receptors that are embedded in this matrix. These receptors are proteins such as ZP3 and ZP2, which are integral components of the zona pellucida.

When a sperm encounters the zona pellucida, the binding of its surface ligands to ZP3 and ZP2 triggers the acrosome reaction, allowing the sperm to penetrate the zona and reach the plasma membrane of the oocyte.

Other structures listed in the options do not serve this function in mammals:

• The perivitelline space is the region between the zona pellucida and the oocyte membrane, not a site of receptor expression.

• The corona radiata consists of follicular cells that surround the zona pellucida, but they do not contain the sperm‑binding receptors.

• The vitelline membrane is the egg envelope found in non‑mammalian species (e.g., birds and reptiles) and is not present in mammals.

Therefore, the receptors responsible for sperm binding in mammals are located on the zona pellucida.