Given that, $a_1,a_2,a_3,a_4,a_5$ are five consecutive odd numbers.
- $a_3-4,a_3-2,{\color{Red} {a_3}},a_3+2,a_3+4$
A new sequence of five consecutive even numbers ending with $2a_3$ will be :
- $2a_3-8, 2a_3-6, 2a_3-4,2a_3-2,2a_3$
The sum of the numbers in the new sequence $=450$
$\Rightarrow (2a_3-8)+(2a_3-6)+(2a_3-4)+(2a_3-2)+(2a_3)=450$
$\Rightarrow 10a_3-20 = 450$
$\Rightarrow 10a_3 = 470$
$\Rightarrow \boxed{a_3 = 47}$
$\Rightarrow a_5 = a_3+4=47+4=51.$
Correct Answer $:\text{B}$