The decimal number 3 is ___ in binary the 2s column plus the 1s column.

a. 11

b. 12

c. 20

d. 21

The answer is "Option a"

Explanation:

In the given question the correct answer is the option a because when we change decimal number 3 into a binary number, It will give "11". To know its decimal number we add both numbers.

for example:

binary to decimal (11) ₂=?

∴ 2¹=2 and 2⁰=1

= 1*2¹+1*2⁰

∵ 1*2+1*1

=2+1

=3

and other options are not correct, that can be described as follows:

In option b, option c, and option d, The computer understands the only binary language, that contains only 0 and 1, and in these options, It contains other value, that's why it is not correct.