Both A and R are true and R is the correct explanation of A.

Both A and R are true but R is not the correct explanation of A.

A is true but R is false.

A is false but R is true.

requires skilled labour

requires low maintenance cost

requires less material

results in less damage due to gradual failure

mean range

maximum range

maximum rise

mean rise

2.5 m

4 m

5 m

7 m

1.2 H to 1.25 H above the datum

1.2 H to 1.25 H above the low water level

1.2 H to 1.25 H above the high water level

1.2 H to 1.25 H above the mean sea level