Ba2Cl
NaS2
The numbers are in subscript
I choose the option A.
The electron absorbs energy from specific wavelength then moving from a lower energy orbital to a higher energy orbital.
Prescribed to you by your doctor.
I would use an over the counter antacids for occasional heart burn. If there are symptoms of acid reflux I would suggest a histamine blocker, or H2-Blockers, such as Ranitidine (Zantac) and Famotidine (Pepcid)
H2O became a vapor when heated because thats the only one that can go back to its normal state, which is what a physical change is.