Which of these is an isoelectronic series?

Examples of isoelectronic species are

N3–, O2–, F–, Ne, Na+, Mg2+, and Al3+ (1s22s22p6). Another isoelectronic series is P3–, S2–, Cl–, Ar, K+, Ca2+, and Sc3+ ([Ne]3s23p6).

The size depends on the number of protons for the atoms or ions that are isoelectronic

it's all four options.