Task is Added.
 And Below Validation are applied as per discussion with Ankitbhai.
 
1)  "Optional Suject Assinged to student, Delete all the optional subject first to change it 
2) Result Generated for student, Delete all the result / markentry first to change it
3) Co-Scholastic Result add for student, Delete all the Co-Scholastic Result first to change it 
4) Optinal subject grade add for student, Delete all the Optinal subject grade first to change