Im no expert but I usually consider first crack and second crack when there are a number of cracks in a cluster, so (b).
Are you getting 7 minutes between first crack and second crack? - if so this seems a bit long to me. This may be because the P2 profile has a large power drop around the 2/3 mark that may stretching out the roast too long with this weight of beans. If the beans are not to your liking but you want to stick with the P2 profile I would suggest upping your bean weight to 350g or you can always change your profile to say P3 or P4.
Experiment and have fun!