Of the elements listed, which has the highest first ionization energy?

Berelium(Be) highest first ionization energy.

It takes more energy to remove the initial electron from beryllium than from boron because beryllium has a stable full electronic configuration$\left(1s^{2}2s^2\right)$, but boron has an electronic configuration $\left(1s^{2}2s^{2}3s^1\right)$that requires less energy than beryllium.