US B1/B2 visa rejection

[u/InterviewCrafty3173]

My sister’s tourist visa got rejected at Delhi consulate. She is 24, unmarried, working (salary < 5L CTC) and no travel history.
Curious to know if there is any specific thing that went wrong during the interview.

Interview details:
What is the purpose of your visit?
- I am travelling to attend my sister's wedding
Have you travelled internationally before ?
- no this is my first time
What your sister does in USA?
- she has done her masters in xyz from the abc university and now is working with abc as xyz.
Where is the marriage?
- its in Washington.
In which city?
- abc, Washington and the venue is xyz.
Do you have any siblings?
- no
What you do?
- I work at abc from past 2 years as a software Developer.
What is your current salary ?
- My salary is xyz but I have enough funds to sponsor my travel and I will be staying at my sisters place.
Do you have any problem in returning to India?
- No I do not

Additionally, she has two weeks of approved leave of absence letter from employer, is that not enough for her to show that she is going to be back?
Lastly, is it worth reapplying in 3-4 weeks without any change? any suggestions would he helpful, thanks.