Answer:
Its D. d
Step-by-step explanation:
I believe someone else said this same thing but I'll explain it a bit differently and more in-depth.
There is this common formula that's used a lot, it's r*t=d, rate * time = distance. In this formula, we see that distance is represented as d, so we can assume that in this scenario, the distance will also be represented by d.
When doing math, you're going to wanna make the variables simple and understandable, say you're doing a coin problem with nickels and dimes, you're going to wanna label your variables for nickels "n" and your variables for dimes "d" just so you don't get confused.
Now if you have another problem like this, you don't even have to ask brainly, you can just make an educated guess like this.
