Two particles are thrown simultaneously from points A and B with velocities u₁ and u₂​ respectively. Find the minimum separation between the two particles.

a) ∣u₁​−u₂​∣
b) ∣u₁​+u₂​∣
c) ∣u₁²​​−u₂²​∣
d) √u₁²​+u₂²