In the circuit, the present value of Z is 1. Neglecting the delay in the combinatorial circuit, the values of S and Z respectively, after the application of the clock will be

The correct option is:
$S=1,Z=0$

Step-by-Step Explanation:

1. Analyze the Circuit from the Diagram:
From the provided circuit image, we can identify two main stages:
* A Combinatorial Circuit with three inputs: $X$, $Y$, and the feedback signal $Z$. The output of this circuit is labeled as $S$, defined by the expression:
$S=X\oplus Y\oplus Z$
* A D Flip-flop whose input is $D=S$ and whose non-inverted output $Q$ is labeled as $Z$.

2. Determine the Initial (Present) State:
The problem provides the following initial conditions:
* Present value of $Z$ (before the clock trigger): $Z_{\text{present}}=1$
* Inputs: $X=1$ and $Y=0$
Using these values, we calculate the combinatorial output $S_{\text{present}}$ just before the clock edge:
$S_{\text{present}}=X\oplus Y\oplus Z_{\text{present}}$
Substituting the given values:
$S_{\text{present}}=1\oplus 0���1$
Since $1\oplus 0=1$ and $1\oplus 1=0$, we have:
$S_{\text{present}}=0$
This means the input to the D Flip-flop is $D=0$.

3. Calculate the State After the Application of the Clock:
* Updating Z: When the clock trigger occurs, the D flip-flop updates its output $Q$ (which is $Z$) to the value present at its input $D$ right before the clock transition.
Therefore, the new value of $Z$ becomes:
$Z_{\text{next}}=S_{\text{present}}=0$
* Updating S: Because propagation delay in the combinatorial circuit is neglected, the output $S$ responds instantaneously to the change in $Z$.
We calculate the new value of $S$ using the updated feedback value $Z_{\text{next}}=0$:
$S_{\text{next}}=X\oplus Y\oplus Z_{\text{next}}$
Substituting the values:
$S_{\text{next}}=1\oplus 0\oplus 0$
Since $1\oplus 0\oplus 0=1$, we obtain:
$S_{\text{next}}=1$

Thus, after the application of the clock, the values of $S$ and $Z$ are $1$ and $0$, respectively.