How many protons are in an atom represented by 22088ra88220ra?

Answer is: there are eighty-eight (88) protons in an atom.
The atomic number (Z) determines total number of protons and uniquely identifies a chemical element, also the atomic number is equal to the number of electrons.
The atomic number (Z) for this atom (radium) is eighty-eight.
The mass number (A) is total number of protons and neutrons in a nucleus, in this example A = 220.

The answer is b on plato.

True, the standard unit for volume is liters which can be represented by either a lower case "l" or a capital "l"