A Proton Is Moving At $3.0 \times 10^{6} \mathrm{~m} / \mathrm{s}$

A proton is moving at $3.0 \times 10^{6} \mathrm{~m} / \mathrm{s}$ and experiences a magnetic force of magnitude $2.5 \times 10^{-16} \mathrm{~N}$ . If the magnetic field makes an angle of $40^{\circ}$ with respect to the velocity of the proton, what is the field's magnitude?

A) $3.3 \times 10^{-4} \mathrm{~T}$
B) $1.7 \times 10^{-4} \mathrm{~T}$
C) $4.1 \times 10^{-4} \mathrm{~T}$
D) $8.1 \times 10^{-4} \mathrm{~T}$
E) $1.6 \times 10^{-3} \mathrm{~T}$