Which of these statements is an example of indexing?

a. “I noticed that the other day, when you were reading, you acted a little rude.”
b. “I have a completely different perspective than an African American.”
c. “I felt ignored when you kept looking at your phone while I was talking.”
d. “I think you are can be selfish sometimes, though you’re usually mature.”

a. “I noticed that the other day, when you were reading, you acted a little rude.”