In the following question, out of the four alternatives, select the alternative which best expresses the meaning of the idiom or phrase: To have at one's fingertips.

Introduction / Context:
This question tests understanding of a common English idiom: "to have at one's fingertips". Idioms are fixed expressions whose meanings cannot always be deduced directly from the literal meanings of individual words. For competitive exams and fluent communication, it is important to understand such phrases because they are frequent in reading passages, dialogues, and listening materials.

Given Data / Assumptions:

• The idiom is "to have at one's fingertips".
• The options describe different possible metaphorical meanings.
• The core idea of the idiom relates to knowledge or information.
• We assume a standard British or general international English understanding of the phrase.
• The correct option should capture quick and easy access to information.

Concept / Approach:
The idiom "to have something at one's fingertips" means to have information or skill readily available and easy to use. It suggests that facts, figures, or details are so well learned or memorised that one can produce them instantly, as if they are right at the fingertips, ready to be tapped. It does not literally refer to typing speed, playing instruments, or physical dexterity, although the imagery involves the fingers.

Step-by-Step Solution:
Step 1: Recall the usual usage: "The lawyer had all the case details at her fingertips", "The teacher had statistics at his fingertips". Step 2: Examine option "To be very fast on the keyboard". This relates to typing speed and physical movement, not primarily to knowledge. Step 3: Examine "To be adroit with a percussion musical instrument". This implies skill in playing an instrument, again focusing on physical ability. Step 4: Examine "Recall of factual information at one's command". This describes exactly having facts or data readily available in memory. Step 5: Examine "To carefully note down minute details". This speaks about recording information, not having it instantly available in the mind. Step 6: Examine "To be skilled in manual work". This is again about practical hand skills rather than mental recall. Step 7: Conclude that "Recall of factual information at one's command" is the only option that matches the idiomatic meaning.

Verification / Alternative check:
We can verify by placing the idiom into sample sentences. "As an experienced doctor, she had a huge range of medical facts at her fingertips" clearly implies quick mental access to information, not typing speed or manual skill. Dictionary definitions support this, stating that to have something at one's fingertips means to have it easily and immediately available. Comparing this to each option confirms that the third option, about recall of factual information at one's command, is an accurate paraphrase.

Why Other Options Are Wrong:
"To be very fast on the keyboard" misinterprets the metaphor literally, focusing on fingers and speed rather than knowledge. "To be adroit with a percussion musical instrument" again takes the finger imagery literally and shifts it to music, which is not the intended meaning of the idiom. "To carefully note down minute details" describes a method of recording information but says nothing about having that information instantly ready in memory. "To be skilled in manual work" is about physical craftsmanship and does not involve the concept of quick mental recall.

Common Pitfalls:
A frequent error is to interpret idioms literally, especially when they refer to parts of the body like the head, hand, or fingertips. Another pitfall is choosing options that mention fingers or hands even when they miss the mental aspect of the expression. To avoid this, whenever you see an idiom, think of how it is used in real-life sentences and what role it plays in communication: does it express knowledge, speed, surprise, or something else. That mental check will guide you to the correct paraphrase.

Final Answer:
The idiom "to have at one's fingertips" means recall of factual information at one's command.