Respuesta :
The statement would be needed to strengthen it would be academic language. Obviously this is because you would not use the phrase “in-your-face-proof”...
Answer:
The answer d) academic language
Explanation:
The argument already contains facts/statistics in the phrase "15 percent increase," while the argument/claim is written in an informal tone and uses numerous expressions/idioms. Therefore, it could be best strengthened by a more formal tone/academic language.