Step 1: Let the present age of Sunitha be x.
Since Reena is twice as old as Sunitha, Reena's present age will be \( 2x \).
Step 2: Using the Age Relationship 3 Years Ago
Three years ago, Sunitha’s age was \( x - 3 \), and Reena's age was \( 2x - 3 \). According to the problem, three years ago, Reena was three times as old as Sunitha:
\[
2x - 3 = 3(x - 3)
\]
Step 3: Solving the Equation
Simplifying the equation:
\[
\begin{aligned}
2x - 3 &= 3x - 9
2x - 3x &= -9 + 3
-x &= -6
x &= 6
\end{aligned}
\]
Step 4: Reena's Age
Since Sunitha's present age is \( x = 6 \), Reena's present age is \( 2x = 2(6) = 12 \).
Thus, Reena is 12 years old.
Therefore, the correct answer is (4) 12 years.