A. Thelowestflightlevelavailableforuseabovethetransitionaltitude.
B. Thelowestflightlayeravailableforuseabovethetransitionheight.
C. Thelowestflightlevelavailableforuseabovethetransitionheight.
D. Thelowestflightlayeravailableforuseabovethetransitionaltitude.