If I had to I'd pick #2 because I value breakpoints too much, but most people here might say #3 due to higher overall stats.
Truth is I wouldn't power up any Entei right now. No current T3 and up raids are weak to fire besides Scyther who has a more exploitable double weakness to rock. Gen 4 is looming around the corner too, introducing Heatran who stands to make all existing fire specialists obsolete.