It can be inferred from the passage that in language studies, a “corpus” is:

A

I and III only

Explaination

This Reasoning Within the Text question concerns a piece of linguistics terminology. We are told regarding the research material that “the study compares academic e-mails and academic letters in paper format retrieved from the correspondence of four senior researchers” and the emails were organized according to the goals of the message. The passage makes clear that the messages represent a sampling of typical work emails, and thus reflect everyday use of language. We can also infer that enough emails were chosen to divide up into categories and provide substantial data, suggesting a relatively large body of texts. II. Nothing in the passage suggests the emails were individually chosen for any.