This is for your information that reasons cannot be asked through RTI applications. Queries like If, Can, Whether, Why, How etc., cannot be asked in RTI application as it does not come under Section 2 (f) of the RTI, Act 2005 which defines Information. We can only ask for those information which is in some form of existing records like rules, guidelines, policies, etc.
The Hon'ble Supreme Court by judgment in Central Board of Secondary Education (CBSE) Vs Aditya Bandopadhyay (2011) 11 SCR 1028, declared that all the exams, conducting bodies are bound to disclose answer sheets to the students or candidate.
So, a student can ask for his evaluated answer sheets through RTI.