Sorry, your answer is incorrect. Check to see if all the truss cells are triangular, or use the stability criterion to determine if the truss has a sufficient number of members.

You are absolutely RIGHT! But do you know what needs to be done to make it stable?

A quick look at the truss indicates the presence of a quadrilateral cell in the middle of the truss. Thus, it is not a stable truss. To make it stable, we need to add another bar that would transform the quadrilateral to two separate triangles as shown in the figure below. We could also use the stability criterion to determine whether the truss would stay rigid or collapse. The truss has 10 joints and 16 members. According to the stability criterion, the truss has to have at least 17 members to be stable. Therefore, this is not a stable truss.