What is the general 28-day crushing strength of concrete for mono block prestressed concrete type sleeper?

What is the general 28-day crushing strength of concrete for mono bloc

1.	What is the general 28-day crushing strength of concrete for mono block prestressed concrete type sleeper?
A.	525kg/cm<sup>2</sup>
B.	600kg/cm<sup>2</sup>
C.	1676kg/cm<sup>2</sup>
D.	100kg/cm<sup>2</sup>
Answer» B. 600kg/cm<sup>2</sup>