Better alternative for unmarried Sister Visa App

[chi]

I would like to invite my unmarried sister (age 27 years, profession - doctor), to USA on tourist visa. We are three siblings of which my elder sister (US citizen) and i (H1B) are in USA. What is the best alternative (with better chances of getting visitor visa)?

1) Should my elder sister (US citizen) sponsor my younger sister? OR
2) Should i (H1B holder) sponsor my younger sister?

Both of us will be able to produce necessary documents but whose sponsorship will hold more weight?

Also, apart from the younger-sisters employment at hospital and bank statements, should she show any other documents to prove ties with India? Our parents have 10 yr multiple visa for USA and they are in India.

Also, my younger sister is not that fluent in english so should we schedule for Visa interview at Mumbai with Gujarati as language of interview?

Any help or guidance is highly appreaciated.

[immihelp]

Anyone can sponsor. It does not matter.

If the person is not fluent in English, interview in regional language such as Gujarati can be scheduled.