B. Formal
The tone is formal because it presents the information in short, clear sentences and uses vocabulary, like "coincidental", "incidents", "dialogues", and "similarities" are all words that could be relaxed for an informal tone. The use of the word "persons" especially, gives the indication that the tone is formal.
The correct answer is A.
Answer B is a claim -- but it does not provide any supporting evidence or facts to prove its truth. Without supporting evidence it is basically an opinion.
Answer A provides evidence for the claim by listing the many resources that students can access via handheld devices. This statement better proves the truth of the opinion.
Matching is as shown below:
1. pronoun with no specific antecedent - indefinite pronoun
2. determined by function - case
3. consistency between subject and verb or pronoun and antecedent - agreement
4. subject case - nominative
5. clarifies or renames preceding noun - appositive
6. clause with implied subject or verb - elliptical clause
7. adjective phrase without word to modify - dangling construction
8. points out which one - demonstrative pronoun
9. two-word pronoun - reciprocal pronoun
Answer:
b. It adds credibility to the argument they wish to prove.
Explanation:
References from other sources adds credibility to a writers argument, especially when it comes from an expert source. References give an agrument more evidence and support and shows that they are people who agree with said agrument.
All of the other choices show a negative, or false effect of including a reference. Thus, the best option is b.
hope this helps!