Final answer:
The phrase 'Like Peter,' is the most suitable addition to the beginning of sentence 9 to create a better connection to the text by comparing the exercise's difficulty for non-native speakers to the experiences of a specific person.
Step-by-step explanation:
In evaluating the provided choices and considering the context of sentence 9, which states, '... acknowledging that this exercise may be less intuitively obvious to non-native English speakers', the phrase that would best make a better connection to the text at the beginning of this sentence is 'Like Peter,'. This is because noun phrases that act as subject complements often start with the preposition 'like', and it would offer a comparison to a person (Peter) thereby providing a more concrete example to which the reader can relate. It also helps in creating a cohesive and clearer understanding within the narrative by drawing a parallel that can be immediately recognized by the reader.
Transitional phrases, as explained in the given materials, are essential in showing the relationship between ideas, and the nuance provided by 'Like Peter,' fits well within this goal. Additionally, by comparing the exercise's difficulty for non-native speakers to the experiences of a specific person, the writer can create empathy and a more personal connection for the reader.