Most of the issues discussed in the meeting were trivial and only a few were . . . . . . .

The correct answer is: E. significant

The other options are not correct because:

• Practical does not mean important or significant. It means useful or feasible.
• Complex does not mean important or significant. It means complicated or difficult to understand.
• Interesting does not mean important or significant. It means arousing curiosity or interest.
• Irrelevant does not mean important or significant. It means not relevant or applicable.

The word “significant” means important or having a great effect. In the context of the question, it is clear that the issues discussed in the meeting were not all important. Only a few of them were significant.