The open-loop DC gain of a unity negative feedback system with closed loop transfer function   is ____Select one:a. 4b. 4/9c. 4/13d. 9

To find the open-loop DC gain of a unity negative feedback system with a closed-loop transfer function, we need to follow these steps:

Step 1: Identify the closed-loop transfer function. In this case, the closed-loop transfer function is given as "____".

Step 2: Determine the open-loop transfer function. The open-loop transfer function is obtained by removing the feedback path from the closed-loop transfer function. In this case, the open-loop transfer function is the same as the closed-loop transfer function.

Step 3: Evaluate the open-loop transfer function at DC (zero frequency). This means setting s (the Laplace variable) to zero in the transfer function.

Step 4: Simplify the expression obtained in step 3 to find the open-loop DC gain.

By following these steps, we can determine the open-loop DC gain of the given system.