please show work

3. (10 points) In the Bridges of Knigsburg network with four regions and seven bridges, it is impossible to construct a round trip that visits all regions, while crossing each bridge exactly once. (a). Specify the smallest number and locations of additional bridges to add to the original Knigsturg network in order to corstruct such a round trip that starts and ends at region A, visits all regions, and uses each bridge exactly once. Then write out the sequence of ares that define the round trip (this is known as an Eulerian circuit). (b). Specify the smallest number and locations of ndditional bridges to add to the original Konigsburg network in order to constract a trip that starts at region A and ends at region C, visits all regions, and uses cach bridge exactly once. Then write out the sequence of ares that define the trip (this is known as an Eulerian path)