Final answer:
Only conjugated dienes react with ethene through the Diels-Alder reaction to form a six-member cyclic product; isolated and cumulative dienes would not typically undergo this reaction.
Step-by-step explanation:
When identifying which dienes will react with ethene through the Diels-Alder reaction, one must consider the structure of the diene. A conjugated diene, such as butadiene, can undergo this reaction with ethene to produce a six-member cyclic product.
This reaction forms a cyclic six-member transition state and is characteristic of conjugated dienes since their structure allows for this process to occur. Isolated and cumulative dienes do not normally participate in this type of reaction.