Telecommunications, but most fitting answer would be Technology & Programming

Telecommunications

Telecommunications (implied by being on the system category but the category that fits the most would be) Technology & Programming

Mobile telecommunications service

Mobile Technology & Telecommunications is not in the list but "Technology & Programming" is the most relevant category.

Telecommunications

Software technology is directly associated with telecommunications which is the sector in which Telegram operates. Technology & Programming

Telecommunications, more specifically (though the list isn't too wide-ranging for that), "Technology & Programming"

Telecommunications/ can fall under multiple categories, but most relevant one is: Information Technology

Mobile app development, Cloud Computing, Big Data, Telecommunications, Cloud storage, Video conferencing does not have it's exact suitable category but mostly related to other "Technology" and "Entertainment" has "Media ".

Telecommunications.

Telecommunications/ Technology companies