I think it’s A but I’m not sure
Answer: 
Step-by-step explanation:
Since we have given that

Now, we know the rule for summation , we'll apply this ,

Now, it becomes geometric progression, so we us the formula for sum of terms in g.p. which is given by

So, our equation becomes ,

Hence ,

48 ÷ 6 = 8
16 ÷ 2 = 8
So you need 8 vans
I hope that helps!