A Proton Is Moving at 3

A proton is moving at 3.0 × 10⁶ m/s and experiences a magnetic force of magnitude 2.5 × 10⁻¹⁶ N. If the magnetic field makes an angle of 40° with respect to the velocity of the proton, what is the field's magnitude?

A) 1.7 × 10⁻⁴ T
B) 3.3 × 10⁻⁴ T
C) 4.1 × 10⁻⁴ T
D) 8.1 × 10⁻⁴ T
E) 1.6 × 10⁻³ T