Which of the following AVAs is located within Solano County?

Carneros is indeed the correct answer because it is an American Viticultural Area (AVA) that straddles both Napa and Sonoma Counties, with a portion located in Solano County. This area is known for its cooler climate, heavily influenced by maritime breezes from San Francisco Bay, which allows for the cultivation of grapes such as Chardonnay and Pinot Noir.

Stag’s Leap District, while renowned for its Cabernet Sauvignon and part of Napa Valley, is not located within Solano County. Similarly, Sonoma Coast and Fountaingrove District are also situated in Sonoma County but do not extend into Solano County. Thus, Carneros is the only AVA from the list that is shared with Solano County, making it the correct choice.