Correct Answer: Dire

Solution : The right choice is the fourth option.

Acute typically refers to a situation or condition that is severe, intense, or critical. Similarly, dire also conveys a sense of urgency, seriousness, or extremity, making it a suitable synonym for acute in this context.

The meanings of the other words are as follows:

• Chronic: This refers to something (often a disease or condition) that is long-lasting or persistent, typically opposite in meaning to acute.
• Faithful: This word describes someone who is loyal and steadfast. It's often used in the context of relationships or allegiances.
• Obtuse: It can mean not sharp-edged or pointed, or, more commonly, slow to understand or insensitive. It's also the term for an angle greater than 90 degrees and less than 180 degrees in geometry.

Therefore, the right answer is dire.