Answer:
(a) 50 dB
Step-by-step explanation:
It is given that someone gives training to dog that it will run for food when h whistles a 60 dB whistles and it is also given that dog will not come when he whistles a 70 dB we have to tell that when there is peak shift effect then whistle would lead to the dog fastest running.The dog will run fast for food when there is a whistle of 50 dB when thee is a peak shift effect.
so option (A) will be the correct option