a. She may be attending the parent-teacher meeting.
b. She might be attending the parent-teacher meeting.
c. She could be attending the parent-teacher meeting.
In which of the sentence/sentences above do/does the underlined modal/s express/es a good possibility?

The correct answer is Option B (a only).

Key Points:
• Concept: Degrees of Possibility expressed by Modal Auxiliaries.
• May expresses a strong or good possibility (around 50% or higher chance).
• Might and Could express a weak, remote, or doubtful possibility.
• Explanation: Sentence 'a' uses 'may', which expresses a 'good possibility'. Sentences 'b' and 'c' use 'might' and 'could', which express weaker or remote possibilities.
• Official Key: Option 2 ('a only') is the official correct answer.
• Key Takeaway: Remember: 'May' denotes a good possibility, while 'might' and 'could' express remote or weak possibility.