please select the best answer from the choices provided

Answer:
[tex]\sqrt{122}[/tex]
Step-by-step explanation:
Given that,
Vector n = 4i-j
Vector m = 3i+3j
We need to find the value of m+2n.
Put all the values,
m+2n = (3i+3j)+2(4i-j)
= (3i+3j)+8i-2j
=11i+j
Magnitude of vector,
[tex]|m+2n|=\sqrt{11^2+1^2} \\\\=\sqrt{121+1}\\\\=\sqrt{122}[/tex]
So the correct option is (c).