The correct answer is A. Self-assured
Step-by-step explanation:
A hyphen (-) is a short dash used to link words, this applies in the case of nouns with multiple words such as "wife-to-be", and also in the case of a set of words that act as a modifier or adjective such as "half-baked cookie". Additionally, the hyphen should never be used to separate essential parts of a word.
According to this, the pair of words that correctly uses a hyphen is "self-assured" because these words form a compound adjective and therefore by using a hyphen to join them it clarifies the meaning depends on both terms, considering this word means to have confidence in oneself, for example, "a self-assured woman" Alos, other options such as self-ish, self-less or self-lessness are not supposed to have a hyphen because they are words by themselves and thus they should be written as selfish, selfless and selflessness.