Pls solve dis question calculate the percentage by mass of all the elements in calcium hydroxide

Given that the chemical formula for calcium hydroxide= (Ca(OH)2)

Using the above formula, we calculate the formula mass of this compound.  

For calcium hydroxide, the formula mass can be calculated as,  

Formulamass=onecalcium

1CA (a/mu = 40) = 40

20 (a/mu = 16) =2×16=32

2H (a/mu = 1) = 2 x 1= 2

%Ca=  40/ 72   ×100

%Ca= 54%

plz brainliest :)

c) should be the answer.