Dear aspirant,

You haven't mentioned any mode of exam but let's say, if you're talking about NEET, the eligibility criteria is:

(a) Open to Indian Nationals only.

(b) Only wards/widows/wives of Defence Personnel from Army, Navy & Air Force from Priority-I to Priority-IX are eligible for the scheme.

(c) Selection of candidates for Central seats reserved for Govt of India Nominee will be made on the basis of marks obtained by the student in National Eligibility Cum Entrance Test (NEET) conducted by CBSE. Candidates who do not qualify the NEET should not apply.

(d) All cases of disability in r/o of defence personnel (P-III & P-IV), which are due to reasons Aggravated by military service (Not Attributable) are not eligible.

(e) Wards of civilians/civilians working in AFHQ/MoD, DRDO, wards of personnel from Para Military/CAPF are not eligible.

(f) This facility is admissible for only one member of the family.

(g) Candidates should have attained the age of 17 years on 31 December of the academic session in which the admission is sought for.

There is no marks mentioned, but one must qualify in the exam.

For more details, kindly visit this link http://ksb.gov.in/writereaddata/DownLoad/MBBSInstructions.pdf

Hope this helped!