Explanation:
Concept overview / definition
Key idea: Standard sea-level atmospheric pressure is represented by a conventional reference value used in climatology and meteorology.
It can be expressed in different units, but the most common exam-friendly form is in millibars (or hPa).
Why the correct option is correct
The correct option states the standard sea-level pressure in the commonly used unit for maps and basic climatology.
This value is widely used as a baseline in interpreting pressure systems and converting readings to comparable sea-level values.
Why the other options are incorrect
Options that place the standard sea-level pressure far below or far above typical values are incorrect because they do not match the established standard reference used in meteorological practice.
Options that mix unrelated units without equivalence (or give unrealistic magnitudes) are designed distractors for rote learners.
UPSC exam tip / common confusion
Memory aid: Standard sea-level pressure is close to “one-thousand” in millibars/hPa.
Do not confuse it with temperature standards or with local station pressure at high altitude, which can be much lower than the standard baseline.
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