Isn't (B) a conventional explanation? (e.g. the B-52 bomber explanation?)
More importantly, how have you established that "no conventional explanation can account for this sighting"? I could list about 10 possible conventional explanations off the top of my head. Have you really considered all the possibilities?
By the way, you should always take accounts of how fast UFOs move, how far away they are etc. with a grain of salt. Observers tend to be notoriously inaccurate about such things.
Please list them.
We've been through flares, chinese lanterns (which I shot down with accuracy provided by help from Phlog and his little video). If you want me to cover this evidence again, I will.
Planes? Aye right, plenty reasons why that doesn't fit the bill either. Helicopters are equally the same. Rockets maybe in your 10 lists of things? Well, I don't know any rockets which fits the description of the Pheonix Lights.
Birds maybe James?
Common, list your 10 conventional explanations which can account for the pheonix lights. I'll assume you have not really studied the evidence to it's strongest and went through why any of the conventional explanations will not suffice, but don't worry, I'll be easy with you.