Its B because 3/10ths is a little bit more than 0.35, but way less than 0.41
X^4+ 3x^3+4x^2-8 | x+2 = x^3+x^2+2x-4
-x^4-2x^3
-----------------------
x^3+4x^2-8
-x^3-2x^2
-------------------------
2x^2-8
-2x^2-4x
--------------
-4x-8
4x+8
----------------------------
/ /
is a factor because (x+2)(x^3+x^2+2x-4)=x^4+3x^3+4x^2-8
