Which of these is a sharp, bitter, or cutting expression or remark?

Sarcasm is "a sharp, bitter, or cutting expression or remark; a bitter gibe or taunt". Sarcasm may employ ambivalence, although sarcasm is not necessarily ironic. Most noticeable in spoken word, sarcasm is mainly distinguished by the inflection with which it is spoken and is largely context-dependent.

Understanding the subtlety of this usage requires second-order interpretation of the speaker's or writer's intentions; different parts of the brain must work together to understand sarcasm. This sophisticated understanding can be lacking in some people with certain forms of brain damage, dementia and sometimes autism, and this perception has been located by MRI in the right parahippocampal gyrus.

Research has shown that people with damage in the prefrontal cortex have difficulty understanding non-verbal aspects of language like tone, Richard Delmonico, a neuropsychologist at the University of California, Davis, told an interviewer. Such research could help doctors distinguish between different types of neurodegenerative diseases, such as frontotemporal dementia and Alzheimer's disease, according to David Salmon, a neuroscientist at the University of California, San Diego.