Correct Answer: redius

Solution : The first option is the correct answer.

The incorrectly spelled word is redius. The correct spelling is the radius, which means the distance from the centre to the outer edge of a circle.

The meanings of the other options are as follows:

• Realm refers to a kingdom or domain, often used figuratively to refer to a sphere of activity or knowledge.
• Resemble means to have a similar appearance or quality.
• Reliable means dependable and trustworthy.

Therefore, the correct answer is radius.