The question below has one blank, which is indicating that something has been omitted. Find out which option can be used to fill up the blank to make it meaningfully complete.
The scientist had to ________ the instrument against a standard before taking precise measurements.

Correct option is A

The correct option to fill in the blank is (a) calibrate.
“To calibrate” is to adjust an instrument to match a known standard, ensuring accuracy—precisely what is needed before precise measurements. (Hindi: अंशांकन/मानक के अनुसार समायोजन करना).
Example: Technicians calibrate the sensors daily to avoid drift.
Explain why other options are incorrect.
· aligns: 3rd-person singular form; grammar mismatch after “had to” (Hindi: सीध में करना).
· sanitize: to disinfect/clean (Hindi: कीटाणुरहित करना); not an accuracy procedure.
· mount: to install (Hindi: स्थापित करना); different action.
· duplicate: to make a copy (Hindi: प्रतिलिपि बनाना); unrelated to standardization.