The correct answer is "was sending".
**Explanation:**
The sentence implies that Tony was in the middle of sending text messages at a specific time (8 p.m.) in the past. This suggests the use of the past continuous tense. The past continuous tense is formed with "was/were + verb-ing". Since "Tony" is a singular subject, we use "was". Thus, the correct option is "was sending".
**Translation to Russian:**
Выберите правильный вариант. Тони ___ текстовые сообщения в 8 вечера.
Правильный ответ: Тони отправлял текстовые сообщения в 8 вечера.
Таким образом, правильный вариант ответа: **was sending**