Correct Answer: engaging

Solution : The right choice is the first option

Explanation :

• Tedious means something that is boring, monotonous, or dull, so engaging is its opposite, meaning interesting, captivating, or involving.
• Informative conveys valuable educational content or knowledge.
• Idle suggests a lack of activity or purpose, often in a resting state.
• Boring denotes something uninteresting or lacking in excitement or engagement.

The correct sentence is: "The professor's lectures are very conventional and so engaging ."