A rectangular paper of $20\text{ cm} \times 8\text{ cm}$ is folded 3 times. Each fold is made along the line of symmetry, which is perpendicular to its long edge. The perimeter of the final folded sheet (in cm) is

Let the initial dimensions of the rectangular sheet be $L_0 = 20\text{ cm}$ and $W_0 = 8\text{ cm}$.

Each fold is made along the line of symmetry perpendicular to the current longer edge, halving the length of that edge:

1. First Fold:

   • Current dimensions: $20\text{ cm} \times 8\text{ cm}$ (long edge is $20\text{ cm}$).

   • Folding halves the $20\text{ cm}$ side to $10\text{ cm}$.

   • New dimensions: $10\text{ cm} \times 8\text{ cm}$.

2. Second Fold:

   • Current dimensions: $10\text{ cm} \times 8\text{ cm}$ (long edge is $10\text{ cm}$).

   • Folding halves the $10\text{ cm}$ side to $5\text{ cm}$.

   • New dimensions: $5\text{ cm} \times 8\text{ cm}$.

3. Third Fold:

   • Current dimensions: $8\text{ cm} \times 5\text{ cm}$ (long edge is now $8\text{ cm}$).

   • Folding halves the $8\text{ cm}$ side to $4\text{ cm}$.

   • New dimensions: $5\text{ cm} \times 4\text{ cm}$.

Perimeter of the final folded sheet:

Hence, the correct option is A.