The grade of plain concrete to be used in sea water or structures exposed to sea water, should be
A.	M lO
B.	M 15
C.	M 20
D.	M 30
Answer:B
The grade of plain concrete to be used in sea water or structures exposed to sea water, should be
A.	M lO B.	M 15 C.	M 20 D.	M 30