Step 1: Context: Dave’s seriousness leads to explaining jokes, normally unspoken.
Step 2: Options: Viscous (thick), Pusillanimous (timid), Facetious (joking), Filial (familial),
Sportive (playful); Querulous (complaining), Pithy (concise), Tacit (unspoken), Luminous
(bright), Austere (severe).
Step 3: Facetious (humorous) comments and Tacit (implied) jokes fit his reaction.
Step 4: Others don’t match joke context or unspoken nature.