Where is the red dot located

Answer:
B. [tex]\sqrt{18}[/tex]
Step-by-step explanation:
While we don't know exactly where it is, we know that it's not A, as [tex]\sqrt{10} < 4[/tex].
We know it's not D, because [tex]\sqrt{12} < 4[/tex]
We're left with B and C. We know that [tex]\sqrt{24} > \sqrt{20.25} = 4.5[/tex] so it's not C either.
B is the only sensible answer.