Consider the following compounds and the given mass spectral data:
a. M+ doublet at m/z 156 and 158.
b. Base peak at m/z 91.
c. A strong peak at m/z 41.
d. Base peak at m/z 43.
Match each structure with its characteristic ions from the given data.

• A. Compound I: M+ doublet at m/z 156 and 158
  Compound II: Base peak at m/z 91
  Compound III: Base peak at m/z 43
  Compound IV: A strong peak at m/z 41
• B. Compound I: Base peak at m/z 91
  Compound II: M+ doublet at m/z 156 and 158
  Compound III: Base peak at m/z 43
  Compound IV: A strong peak at m/z 41
• C. Compound I: Base peak at m/z 91
  Compound II: M+ doublet at m/z 156 and 158
  Compound III: A strong peak at m/z 41 Compound IV: Base peak at m/z 43
  
• D. Compound I: M+ doublet at m/z 156 and 158
  Compound II: Base peak at m/z 91
  Compound III: A strong peak at m/z 41 Compound IV: Base peak at m/z 43
  

Answer: (B)