Answer:
The options are not given in the question. All of them are correct and given as follows.
1. Salutation
As the salutation is a compulsory part in any type of a letter, due to different practices of different cultures there will be a difference in that part.
2.Tone & language
There will be a difference in writing a letter in native language and in the foreign language.
3. level of specifying information
It's obvious that explaining and specifying an information to the person of your own culture is much easier then explaining to the foreigner so there lies a difference in explanation too.
Explanation:
