Variant vs. Alternative

“Choose the correct variant”… “I would go for variant 1”… “What is your variant?”

These are expressions that are often heard from the native speakers of Russian. The word «вариант» in Russian does not fully coincide in meaning with the word “variant” in English. However, my students tend to use this “variant” a lot. That is why I have decided to clarify how it sounds for a native English speaker. And this is what my English teacher who is originally British answered:

'Correct variant'? You're kidding! I know native English teachers who wouldn't even know what that meant! Of course, it's far too formal. A more suitable register would be "which is the correct or best alternative here?"

The title of the message was “orthodoxy” by the way.

English speakers have to admit though that their language does have this word. Let us find out what it really means in English.
Whenever I have my doubts regarding the meaning or usage of a word, I ask Longman. And here goes what Longman thinks about variants:

var‧i‧ant [countable]

1. something that is slightly different from the usual form of something

variant of/on
- This game is a variant of netball.
- a variant on the typical Hollywood hero

2. technical a slightly different form of a word or phrase:
- spelling variants in British and American English

—variant adjective:
- a variant form of the word

Longman doesn’t provide the meaning of this word for mathematical use also (Variant 1, Variant 2), which means that this lexical unit IS an example of ‘orthodoxy’.
What is correct than? The question remains.
There are a lot of correct variants words to replace this one with. They are: alternative, option, version, variation etc.
Hopefully, from now on in all the tests you take, you will go for correct options only!