Which option should I choose while applying for Right issue?

Option 1 : - “I am a shareholder as on Record Date and undertake to hold RE till issue closing date” - Choose this if you held shares on the Record Date.

Option 2 : - “I am renouncee and hold rights entitlement in valid demat account to hold RE till issue closing date” -  Choose this if you bought REs from the market.

Does purchasing REs guarantee that a share will be given or is it like subscribing to an IPO?
If you have X REs, and you apply for X+Y shares. You will get X right shares since you’re eligible. For the remaining Y, there will be a lottery system similar to an IPO.The RTA can consider you for additional allotment depending upon the issue subscription. The amount you’ve paid is kept in an escrow account maintained by RTA and will be refunded if the allotment is not made.

If an individual has 10 shares of a company in one demat account and 5 shares in another, and the company has announced a rights issue in the ratio of 1:15, would they be eligible to exercise the rights?
Eligibility is determined on a folio-wise basis by the RTA. Even though both demat accounts may be linked to the same PAN, the shares would be held in separate folios in the RTA's records. Therefore, in a situation where an individual has 10 shares in one demat account and 5 shares in another, they would not receive the rights entitlement.

What will happen to the amount if I don't receive an allotment in right issue?
The money for any shares not allotted to you will be credited to your bank account by the RTA after the right issue allotment process is complete.