A. A critical tone
B. A reflective tone
C. An optimistic tone
D. A scholarly tone

d. a scholarly tone

Explanation:

It doesn't criticize anything, nor reflect, and it doesn't seem optimistic, so I think its scholarly tone.

b and d

explanation:

voracity is the noun corresponding to the adjective voracious, which means (1) eager to consume a great amount of food, or (2) marked by an insatiable appetite. veracity is far more common than the rare voracity, so the latter is sometimes used in place of the former.