Definitely number 1. Since that is when the yeast is most active, temperature is most important at this stage. In my experience, the beer is about 95% fermented by the time it goes into secondary. It is during the active fermentation where outside factors can affect the yeast, causing the production of undesirables in your beer.
I figured it was the primary as well however this leads me to a related question on secondary temps. If you got a beer in the secondary for say 1 week (2 total with primary) and is basically done fermenting do you think it'd be ok if it is moved from a cooler area (68 in ferm chiller) to a 77-78 environment?
Trying to figure out how to get more than one batch every 3 weeks going now that it's hotter than hell in the desert. Was contemplating shaving 1 week off by doing the above.