Acar is moving with a positive acceleration. which of the following accurately depicts the direction of its velocity?

It is difficult to give you the answer that will suit your task format because you did not attach any following answers to choose the option which would accurately depict the direction of its velocity. But I think I have got right answer and if you have the same in your option list- that is what you need! 
The answer on your question is :
The direction cannot be determined

She reached late; luckily, the bus had not left.

Explanation:

A semicolon is generally used to connect two independent clauses that are closely related. And in the use of the semicolon, the word acting as the conjunction between the two independent clauses must be followed by a comma.

So, the given sentence "She reached late luckily the bus had not left" can be correctly rewritten as "She reached late; luckily, the bus had not left".