None of the above. Just give her a straight answer on your personal understanding of what Scripture says about the eternal fate of her Hindu grandparents. There really aren't that many alternatives.
Just what is the purpose of getting into those judgements? To give her a pompous, protective reason to reject any different teaching from God? To make her choose between the religion of her grandparents and her religion? To make it harder for her to grow to know the Lord and His direction?
Why not just answer her simple question, rather than trying to rationalize why you won't answer it? Is that so hard?
Keep it simple.
I'm all for that! You can't get simpler than "yes" or "no"!
You handle it your way, I'll handle it mine.
And, I am not in the business of judging prior lives. That is for God who CAN judge the totality of the person as man cannot.
We have enough to do with trying to live our current lives.
Wish you would spend the same amount of concern on what God does want people to do.
I tend to think you latch onto questions like this in order to throw up obstacles to others believing since you do not wish to draw people to God but to turn them away from God. That justifies your decision to not accept God in your mind.
Or, it is a cruel objective to hurt the one seeking answers to honest questions. You want to make them know that if they believe, they have to condemn their dead loved ones first. Ask yourself why you so want them to get this judgement. Couldn't each and every one of us have to face the same question about our dead relatives?
The way I handle it in my life? I pray to God to judge them mercifully, I take up for them. As we give mercy to others, we receive mercy. That is all I can do.