Which of the following statements correctly differentiates constitutional isomers from stereoisomers?

• A. Both constitutional and stereoisomers differ in connectivity.
• B. Constitutional isomers differ in connectivity, while stereoisomers differ in spatial arrangement.
• C. Constitutional isomers differ in spatial arrangement, while stereoisomers differ in connectivity.
• D. Both constitutional and stereoisomers differ in spatial arrangement.

Answer: (B)