Which of the following orbitals can hold a maximum of 2 electrons?

The s orbital is the correct choice because it is defined as a spherical region in an atom where the probability of finding an electron is highest. By quantum mechanics, each orbital can accommodate a maximum of two electrons, and these electrons must have opposite spins due to the Pauli exclusion principle.

In contrast, p orbitals can hold up to 6 electrons total (2 in each of the three individual p orbitals), d orbitals can accommodate 10 electrons (2 in each of the five d orbitals), and f orbitals have the capacity for 14 electrons (2 in each of the seven f orbitals). Therefore, the only orbital that can hold a maximum of 2 electrons is the s orbital.