It is completely at their discretion. No need to apply for both. If it is only used for short visits, apply for B1/B2 and if approved, use that. If denied, she can then apply for H4.Also does anyone know whether visa officers cancels all valid visas when one is in interview?
I had mine cancelled when I was applying H-1B transiting from F1 visa. My F visa was crossed out. But I believe that is a different scenario because it involves change of status.
Planning of applying both B and H for her.