What is the minimum AIX level required for an LPAR on a Power 770 to run SMT4?

What is the minimum AIX level required for an LPAR on a Power 770 to run SMT4?

A.
AIX 5.3 TL9

B.
AIX 6.1 TL2

C.
AIX 6.1 TL4

D.
AIX 7.1 TL1