Chinese test: How do you say “sudden” in Chinese? (Elementary)

Exams drive students crazy. Do you remember staying up late cramming for your exams? Today, Li Ming hears that the exam is tomorrow! Let’s see what he says.
Conversation:
              Míngtiān yào kǎoshì, nǐ zhīdao ma?
    Jane：明天       要    考试， 你  知道   吗？
              Á? Tài ___le ba!
Li Ming：啊？太 __ 了 吧！
Question:
What should be put in the above blank? ___
A. 突然 (tūrán)
B. 忽然 (hūrán)

See answer