H4 dropbox or F1 visa?

[AG1991]

Hello,

My wife has an H4 visa valid till June 2019 (And H4 extension is also approved till June 2022). She is currently studying on H4 and is going to visit India in June 2019.
She wants to convert her visa from H4 to F1. What will be the best option - 

1. Obtain the H4 stamping via Dropbox and then apply for F1 as soon as H4 stamping is done.

2. Apply for F1 and if it gets rejected, go with H4 stamping. 

3. Also, is she eligible for H4 dropbox if F1 got rejected?

[RamaKrishna2017]

Option 2 will be good.