Doubt

[Jairo Payan]

Please I need help with this issue.
I was taught that "some" can be used in interrogative questions in the following cases:
When we are making an offer, or a request, and we want to encourage the person we are speaking to, to say "Yes":

I was taking a test and found this question:
Where can I buy__toothpaste?
Options: some/any/a/one

Seemingly the answer is "some" as the answersheet shows.
Why? No offer, no invitation, no clue for a yes answer. (Is that a request or is just a question?)

Another example:
Where can I get "some" information?
Is that a request or is just a question?

In short, in what cases must I use some in an interrogative question, besides the one posted?

Thanks in advance for your help

[Mister Micawber]

.

Where can I buy some toothpaste?
Where can I get some information?

These are both requests for information, not toothpaste (re #1)

Where can I buy some toothpaste?-- presumes that toothpaste is available.
Can I buy any toothpaste?-- an inquiry about travelling in Lower Slobovia.

Where can I get some information?-- presumes the availability of such.
Where can I get any information?-- no idea whether info is available.
.