I think 3 oz of vinegar because
7+4=11
And what plus 8 equals to 11.
And it is 3
The answer is a. the death of aloved one. I am 100% sure.
All the best
The density of liquid can not only help with sciences, but can help you with finding out the murderer of a crime novel. For example, if the killer had poisoned the ice or drink, knowing what the density of liquid can help you find out what poison was used or the antidote.