$1\mathrm{.}3.(5$ pts$)$ Consider two vectors, having magnitudes of $20$ and $50,$ which are added together. Encircle the letter of any one of the following if it is a possible answer for the magnitude of the resultant and briefly explain in words your choice$($s$).$

A$)10$

B$)20$

C$)40$

$($D$)80$