Raul converts numbers in base 10 to base 2. which answer best defends why raul would need to do this?

base 10 numbers cannot use 0 and 1 like the numbers in base 2 can.
base 10 numbers are not able to handle negative numbers, but base 2 numbers are.
base 10 numbers are used for calculations by people, but computers use base 2.
base 10 numbers used by people cannot fit into the format of base 2 numbers.