The distance between two particles is decreasing at the rate of 6m/s. If these particles travel with the same speeds and in the same direction, then the separation increase at the rate of 4m/s. The particles have speeds as –

(a) 5m/s; 1m/s

(b) 4m/s; 1m/s

(c) 4m/s; 2m/s

(d) 5m/s; 2m/s