The correct option is D Oct, 01
Percentage increase in marks in various periodical exams compared to the previous exams are:
For Jun 01 =[(365−360)360×100]
For Aug 01 =[(370−365)365×100]
For Oct 01 =[(385−370)370×100]
For Dec 01 =[(400−385)385×100]
For Feb 02 =[(404−400)400×100]
Clearly, highest percentage increase in marks is in Oct 01.