hello
to solve this question, we just have to find the expression that is equal to 4b
option A
[tex]b+2(b+2b)=b+2b+4b=7b[/tex]option a is incorrect
let's look at option B
[tex]3b+b=4b[/tex]option B is correct
and finally option C
[tex]2(2b)=4b[/tex]option C is correct
from the calculations above, option B and C are the right answers