Final answer:
The follow-up question not appropriate for a guest asking for a martini is 'Up or neat?' because a martini is specifically served chilled without ice ('up') or with ice ('on the rocks'), and 'neat' does not apply to mixed drinks like martinis.
Step-by-step explanation:
When a guest says, "I'd like a martini," the follow-up question that is not appropriate is option c, "Up or neat?" The terms 'up' and 'neat' refer to two different ways of serving a drink. 'Up' in a cocktail context usually means that the drink is shaken or stirred with ice, then strained and served without ice in a chilled glass. On the other hand, 'neat' refers to a single, unmixed liquor poured straight from the bottle into a glass at room temperature, with no chilling, ice, or additional mixers. Since martinis are either served 'up' (chilled and without ice) or 'on the rocks' (with ice), asking 'up or neat?' does not make sense for a martini.
As for the other options, 'Up or on the rocks?' (option a) refers to whether the guest prefers their martini chilled and strained or with ice. 'Twist or olives?' (option b) addresses the guest's preference for garnish, and 'Vodka or gin?' (option d) inquires about the base spirit they would like their martini to be made with. These are all relevant questions when taking a martini order.