Fill in the blank with the correct word from the given options:-Just_…

The correct answer is Option (3) → a little

"A little", "little" and "the little":

• A little means a small amount, but some; it is used for uncountable things (care, caution, water).
• Little without "a" means hardly any; the little means the small amount that there is, a particular amount already known.
• This sentence: only a small amount (of care) is needed when handling chemicals, so "Just a little is necessary".
• Complete sentence: Just a little is necessary for handling chemicals in the lab.
  Example: Add a little salt to the soup.

Why the Other Options are Incorrect?

Option 1: The little — Incorrect. "The little" refers to a particular small amount already mentioned; no such amount has been mentioned here.
Example: He spent the little money he had on books.

Option 2: few — Incorrect. Few is used with plural countable nouns and needs a plural verb ("few are"), not "is".
Example: Few students came to the extra class.

Option 4: Less — Incorrect. Less is a comparative (a smaller amount than something else), and nothing is being compared; "Just less" is not idiomatic.
Example: You should eat less sugar.

Contrast: "a little" (some) goes with uncountable things, "few" with plural countable nouns, and "less" is used only when comparing.