What is the number of operation required to come up with 2 messages having the same message digest in SHA-512?

What is the number of operation required to come up with 2 messages ha

1.	What is the number of operation required to come up with 2 messages having the same message digest in SHA-512?
A.	2<sup>256</sup>
B.	2<sup>512</sup>
C.	2<sup>1024</sup>
D.	2<sup>128</sup>
Answer» B. 2<sup>512</sup>