Correct Answer:
B. useful
Explanation:
The correct answer is useful because the coordinating conjunction 'and' links adjectives with matching contextual tones.
- Step 1 (Contextual Logic): The sentence pairs the missing descriptor with the positive modifier 'informative'. Therefore, the blank space must be filled with a word that shares a similarly positive and constructive meaning.
- Step 2 (Application): The adjective 'useful' perfectly complements 'informative', establishing that the educational session was both highly practical and valuable to the listeners.
- Incorrect Options:
- boring is incorrect because it introduces a negative characteristic that contradicts the positive nature of being informative.
- confusing is incorrect because a confusing presentation fails to properly inform or clarify concepts for an audience.
- dull is incorrect because it implies the lecture lacked engagement or value, directly opposing the helpfulness implied by 'informative'.