B. The Secondary side of the step down transformer.
It increases across a period and decreases down a group. A good way to remember this is that fluorine is the most electronegative atom, and it's to the top right of the table.
Well not calculus because that has nothing, well mostly nothing to do with balancing chemical equation, so B or C. Now for me personally B is way faster, though C is sometimes faster if you get lucky the way to solve it is B
The correct answer is Be+
That is because it lost a single electron but still has the same number of protons, and thus the effective charge attracting each electron is greater, which in turn makes the radius even smaller
