A note on the first question, NS is associated with warm fronts and stable air and its very rare to get embedded CB in NS, although it can unusually happen when the warm sector is very unstable (unusual) and initial frontal lifting sets them off. One would have hoped the forecasters would have picked this up and included the possibility of CBs embedded in the NS, but apparently not and only ISOL CB were forecast not ISOL EMBD CB, and therefore the answer selected is correct.