Concept:
The word volatile refers to something that is unstable, unpredictable, liable to change suddenly, or not remaining constant for a long period.
Step 1: Understand the meaning of the given word.
The word volatile is commonly used for situations, markets, emotions, chemicals, and political conditions that can change rapidly without warning.
Examples:
• A volatile stock market.
• A volatile political situation.
• A volatile personality.
Step 2: Analyse the options.
• Unstable = not steady, likely to change.
• Trespass = to enter a place unlawfully.
• Transient = temporary or short-lived.
• Perpetual = everlasting or continuous.
Step 3: Choose the closest synonym.
Among all the options, unstable conveys almost the same meaning as volatile.
\[
{\text{Volatile} \approx \text{Unstable}}
\]
Therefore, the correct answer is:
\[
{\text{Option (A)}}
\]