Which of the following words corrects the spelling of the underlined word in "Her loss of focus was 'notisable' to all around her"?

The correct choice, "noticeable," accurately reflects the standard spelling of the word used to describe something easily seen or observed. In English, "noticeable" is derived from the verb "notice," with the suffix "-able," which indicates capability. The presence of the "e" before the suffix helps maintain the pronunciation and ensures the word adheres to conventional spelling rules.

When looking at variations of the word, "noticeible" and "noticible" do not adhere to standard English spelling conventions, as they substitute incorrect combinations of letters. The option "noticable" is also incorrect, as it removes the "e" that is essential for the proper form of the word. Thus, "noticeable" is the only option that accurately and correctly reflects standard English usage.