They showed us the B plants

The sentence implies a comparison or a specific type of plant being shown. The options are 'much interesting', 'more interesting', and 'most interesting'. Since 'plants' is plural and the sentence doesn't specify a superlative context, 'more interesting' is the most appropriate comparative adjective.

1. Analyze the context: describing plants shown.

2. Consider the options: comparative and superlative adjectives.

3. Choose the comparative form for plural nouns: 'more interesting'.

more interesting