The given pattern follows a specific rule that can be observed to determine the missing term. Let's analyze the given pattern step by step:

1. A: The first term is "A."
2. B: The second term is "B."
3. AA: The third term is "AA," which means two consecutive "A"s.
4. BB: The fourth term is "BB," which means two consecutive "B"s.
5. AAA: The fifth term is "AAA," which means three consecutive "A"s.

Based on the pattern observed so far, we can conclude that the pattern alternates between two letters, "A" and "B," and the number of consecutive letters increases by one each time.

To determine the missing term, we need to find the next term that follows the same pattern. Let's analyze the options given:

a) BBBB: This option consists of four consecutive "B"s. However, the pattern suggests that the number of consecutive letters should increase by one each time, so this option does not fit the pattern.
b) AAAA: This option consists of four consecutive "A"s. Similar to option a), this option does not follow the pattern correctly.
c) BBB: This option consists of three consecutive "B"s. This fits the pattern because the number of consecutive letters increases by one each time.
d) BB: This option consists of two consecutive "B"s. This also fits the pattern because the number of consecutive letters increases by one each time.

Therefore, the correct answer is option c) BBB, as it follows the given pattern correctly.