Concept:Syllogism: Use Venn diagram or logical deduction to check if conclusions necessarily follow from given statements.Explanation:Statement 1: Some bikes are vans. So there is an overlap between bikes and vans.Statement 2: All vans are trains. So the entire set of vans is inside trains.The overlapping part of bikes and vans is also inside trains. Hence some bikes (those that are vans) are trains. Conclusion I follows.Conclusion II says "No van is a bike". But statement 1 says some bikes are vans, which means some vans are bikes. So conclusion II is false.Only conclusion I follows.Answer:Only I follows.