Step 1: Identify weather elements and their measurement instruments.
- Temperature is measured using a Thermometer (IV).
- Rainfall is measured using a Rain gauge (III).
- Wind velocity is measured using an Anemometer (II).
- Dew is measured using a Dew gauge (I).
Step 2: Establish correct pairings. \[\begin{aligned}(A) &\rightarrow (IV) \text{Thermometer for Temperature}
(B) &\rightarrow (III) \text{Rain gauge for Rainfall}
(C) &\rightarrow (II) \text{Anemometer for Wind velocity}
(D) &\rightarrow (I) \text{Dew gauge for Dew}
\end{aligned}\]
Step 3: Compare with the provided options.
Upon comparison with the given options, only Option 1 accurately reflects the correct pairings.
Final Answer: \[\boxed{\text{The correct answer is 1. (A) - (IV), (B) - (III), (C) - (II), (D) - (I)}}\]