Following is the requirements at different cities:
Total requirement Jyotishamati + Panchal = 700 + 400 = 1100. Out of this. 300 comes through Vaishali – Jyotishamati pipeline. So remaining 800 shall come through Vidisha – Jyotishmati pipeline. Now, requirement at Vidisha = 200. Hence Avanti Vidisha pipeline shall carry 200 (Requirement at Vidisha) + 800 (to be sent further to Jyotishmati) = 1000
So, this is the final situation.
Now all the questions can be answered.
Quality flowed from Avanti to Vidisha = 200 + 100 + 700 = 1000. Hence option (d) is the answer.