Refer to the molecular orbital diagrams of allyl cation (Figure 10.12) and those presented earlier in this

Question:

Refer to the molecular orbital diagrams of allyl cation (Figure 10.12) and those presented earlier in this chapter for ethylene and 1,3-butadiene (Figures 10.8 and 10.9) to decide which of the following cycloaddition reactions are allowed and which are forbidden according to the Woodward- Hoffmann rules.
(a)