Respuesta :

Greenleafable
It really depends on your options. 
Since NH3 solution is a weak base, the option that neutralizes a base is an acid. So find an acid among your options, and here are some examples: HNO3, HCl, etc.
antonsandiego
It would have been much better if you had attached some options to choose. But I think I've got what you mean. I bet that solution is HCl.