Step 1:
Given A die is rolled
$\therefore$ Total number of outcomes n(S)=6
The die has 2 faces with number 1
The die has 3 faces with number 2
The die has 1 face with number 3
Step 2:
Let E be the event of getting a number 1 or 3
$\therefore n(E)=2+1=3$
$\therefore$ Required probability =$\large\frac{n(E)}{n(S)}$
$\Rightarrow \large\frac{3}{6}$
$\Rightarrow \large\frac{1}{2}$
Hence (A) is the correct answer.