Answer:
The bigram level
Explanation:
The bigram level of analysis is an example of the N-gram model(as we can also have trigram). It is used in statistical language models to calculate probability and interprete letters in words based on previous occurrence(preceding word). In other words a bigram(less commonly called digram) makes prediction using conditional probabilities that are based on previous word. A tigram would do just same thing but predicts based on two preceding words.
