In this problem, we need to determine the output Y of the given digital circuit when the input A is 1. The circuit is composed entirely of NOT gates. Let's break down the operation of this circuit step-by-step.

1. The NOT gate is a basic digital logic gate that inverts its input. This means if the input is 1, the output will be 0, and if the input is 0, the output will be 1.
2. Since input A is 1, the first NOT gate will invert this value. Therefore, the output of the first NOT gate is: \text{Output of first NOT gate} = \overline{A} = \overline{1} = 0
3. The output of the first NOT gate (which is 0) now becomes the input to the second NOT gate. The second NOT gate will also invert its input (0 in this case). Thus, the output of the second NOT gate is: \text{Output of second NOT gate} = \overline{0} = 1

Therefore, the final output Y of the circuit is 1.

Hence, the correct answer is:

Option: 1