Can you help me with percent abundance??

Percent abundance is the percentage of all the different isotopes of an element and is used to calculate the average atomic mass. For example 99.98% of all Hydrogen in the universe is meaning hydrogen with 1 proton and 0 neutrons while the remaining 0.02% is   meaning that is the most abundant by  percent.

it's filtration, but this is an assumption so my apologies if i got this

it is b that is the answer.