GENERAL KNOWLEDGE

Detailed explanation-1: -10−12→ Pico. 10−9→ Nano. 10−6→ Micro.

Detailed explanation-2: -Micro (Greek letter (U+03BC) or the legacy symbol µ (U+00B5)) is a unit prefix in the metric system denoting a factor of 10−6 (one millionth).

Detailed explanation-3: -In the SI, designations of multiples and subdivision of any unit may be arrived at by combining with the name of the unit the prefixes deka, hecto, and kilo meaning, respectively, 10, 100, and 1000, and deci, centi, and milli, meaning, respectively, one-tenth, one-hundredth, and one-thousandth.