Among the following, the compound having conjugated double bonds is

Step-by-step solution

Conjugated double bonds are separated by exactly one single bond. In hepta-1,6-diene, the double bonds are at C1 and C6, separated by three single bonds. In hepta-1,3-diene, the double bonds are at C1 and C3, separated by exactly one single bond (between C2 and C3). Thus, it has conjugated double bonds. In hepta-1,4-diene, the double bonds are at C1 and C4, separated by two single bonds. In hepta-1,5-diene, the double bonds are at C1 and C5, separated by three single bonds. Answer: hepta-1,3-diene