Select the correct spelling of the underline word.

They denied having any associasion with the terrorists.

The correct spelling is association.

Here is a step-by-step breakdown of the word to understand its correct spelling:
1. Etymology and Prefix Assimilation: The word comes from the Latin prefix ad- (meaning "to" or "toward") and the verb sociare (meaning "to join together", from socius meaning "companion"). When the prefix ad- is attached to a root beginning with "s", the "d" assimilates into an "s". This results in the prefix becoming as-, which creates the double "s" (ss) at the beginning of the word.
2. Root Spelling: The root portion of the word comes from soci-, which is spelled with a single c. Therefore, the combination of the prefix and root is spelled associ-.
3. Suffix: To turn the root into a noun indicating a state of being or an organization, the standard noun suffix -ation is added at the end.
Combining these components gives: as- + soci- + -ation = association.

Analysis of incorrect options:
- asociation: Incorrect because it is missing the double "s".
- asocciation: Incorrect because it is missing the double "s" and incorrectly doubles the letter "c".
- assosiation: Incorrect because it misspells the root, replacing the "c" with an "s" in the third syllable (using -so- instead of -ci-).