The first part of the sentence describes a woman as “less _________” at work “than she is around her friends,” “but” her staff at work occasionally does see her “in a volatile state,” or a temperamental state that is likely to change quickly. Given the “but,” the blank must be a synonym for “volatile.” “Capricious” and “fickle” can both mean temperamental and likely to change quickly and so are the correct answers. Although “direct” and “explicit” form a pair, they are not synonyms for “volatile” and so are not correct. “Informal” and “pretentious” also do not fit “volatile.”