Dipole-induced dipole interactions, also known as London dispersion forces, occur between a polar molecule and a nonpolar molecule. In these interactions, the polar molecule induces a temporary dipole in the nonpolar molecule, resulting in attractive forces between the two. Let's examine each pair mentioned in the question to determine whether dipole-induced dipole interactions are present.

a. Sif4 and Helium atom:
- Sif4 is a polar molecule due to the difference in electronegativity between silicon and fluorine atoms. It has a net dipole moment, making it capable of inducing a dipole in a neighboring nonpolar molecule.
- Helium atom is a nonpolar molecule with no permanent dipole moment.
- Since Sif4 can induce a dipole in a Helium atom, dipole-induced dipole interactions are present in this pair.

b. H2O and alcohol:
- H2O is a polar molecule due to the presence of two oxygen-hydrogen bonds with different electronegativities. It has a permanent dipole moment.
- Alcohols, such as ethanol, are also polar molecules due to the presence of an oxygen-hydrogen bond.
- Both H2O and alcohol have permanent dipole moments, meaning they can interact through dipole-dipole interactions, rather than dipole-induced dipole interactions.

c. Chlorine and CCl4:
- Chlorine (Cl2) is a nonpolar molecule with no permanent dipole moment.
- CCl4 (carbon tetrachloride) is also a nonpolar molecule with no permanent dipole moment.
- In this pair, both molecules are nonpolar, so there are no permanent dipoles to induce temporary dipoles. Therefore, dipole-induced dipole interactions are not present.

d. HCl and Helium atom:
- HCl is a polar molecule due to the difference in electronegativity between hydrogen and chlorine atoms. It has a permanent dipole moment.
- Helium atom is a nonpolar molecule with no permanent dipole moment.
- Similar to the first example, HCl can induce a dipole in a Helium atom, resulting in dipole-induced dipole interactions.

In summary, dipole-induced dipole interactions are present in pairs a and d (Sif4 and Helium atom, HCl and Helium atom), while pairs b and c (H2O and alcohol, Chlorine and CCl4) do not exhibit these interactions.