The idiom "Straight from the horse's mouth" indicates that the information or statement comes from a direct and reliable source, often someone who is directly involved or has first-hand knowledge. Understanding idioms is an essential part of verbal aptitude, especially for competitive exams where the correct interpretation can influence your score.

1. Meaning Analysis: The expression originates from horse racing, where the most reliable information about a horse's condition or performance is thought to be obtained from those closest to the horse, such as the trainer or the owner. Thus, hearing something "straight from the horse's mouth" means getting information directly from the most credible authority available.
2. Option Evaluation:
   • Ready and eager to engage in an activity: This describes enthusiasm or willingness, not about information reliability.
   • Significantly disturbing business: This suggests disruption or interference but does not relate to the source of information.
   • Information from reliable and authoritative source: This matches the idiom's meaning, hence is the correct choice.
   • Sudden feelings of fear and embarrassment: This describes an emotional reaction and is unrelated to the idiom's context.
3. Conclusion: The correct interpretation of the idiom "straight from the horse's mouth" is that it means obtaining information from a reliable and authoritative source. Therefore, the right answer is the third option.