Quiz on sorting

Q-1
Assume that a merge sort algorithm in the worst case takes 30 seconds for an input of size 64. Which of the following most closely approximates the maximum input size of a problem that can be solved in 6 minutes?

256
256

512
512

1024
1024

2048
2048

please tell me the correct answer
.Correct answer is not displayed and i have tried all the answers
but no one is getting corrected.
I think the correct answer is 512

@ankitdelhi20 Yes you are right. The correct answer is 512 .

Then, why it is marked as incorrect?

We will check it. But 512 is the right answer.