Using the Question we are able to fill the Venn diagram in the following manner. 
Using Condition F, 75 patients were given only 1 medicine 
Hence only B = 75 -25-20-10 = 20 
And Medicine given to A, B, D but not C = 
250-25-20-30-40-20-50-35 = 30 
Exactly 100 people had taken 3 medicines hence Medicine given to B, C, D but not A = 
100-40-20-30 = 10 
And Since C has a total of 210 patients, hence Only B and C = 
210-20-20-30-40-20-50-10 = 20 
Total patients is 500 
Only B and D = 500 – (250+20+20+10+20+20+10) = 150