Which of the following styles has the lowest level of perceived bitterness?

The style that has the lowest level of perceived bitterness is Wee Heavy. This is a Scottish style of ale known for its rich, malty sweetness and higher malt character. Wee Heavy typically has a low level of bitterness compared to other beer styles due to the balance created by the focus on malt rather than hops.

American IPAs and American Pale Ales both emphasize hop flavor and aroma, contributing to a higher perceived bitterness. Czech Premium Pale Lagers, while generally well-balanced, can exhibit a moderate hop profile that might also present a noticeable level of bitterness. In contrast, Wee Heavy is characterized by caramel, toffee, and dark fruit flavors, with bitterness often kept to a minimum to allow the malt complexities to shine through. This focus on malt and the absence of significant hop bitterness make Wee Heavy the style with the lowest perceived bitterness among the choices.