19. A projectile with mass m=0.5 (kg) is launched from the ground at an upward angle, such that the initial vertical component of velocity is v_y0 = 15 (m/s) and the horizontal component of velocity is v_x0 = 24 (m/s). The trajectory of this projectile is given by , where î and ĵ are unit vectors corresponding to +x and +y direction, respectively. Determine the torque acting on the projectile about the origin. [The unit vector k̂ is defined as k̂ = î × ĵ]
(A) (−173.5t)k̂
(B) (−117.6t)k̂
(C) (−192.6t²)k̂
(D) (−123.0t²)k̂