[ ] 1: Astrometrics (+2 Science)
[ ] 2: Biological-Rated Transporter Room (Transporter Capability)
[ ] 3: Science Labs (+2 Science)
[ ] 4: Deflector Array Sensor Analysis (+1 Science, Advanced Scanners)
Personally think this is the way to go here. This gives us 7 science, almost double that of the Enterprise on a hull ⅔ the size. Transporters let us beam away teams down, freeing shuttles for atmospheric survey and other work that takes them farther away from the parent vessel. It also lets us beam away teams back up in a crisis, and internal surveys have a way of getting funky in Star Trek.
As for deflector analysis, this one's a little more up in the air to me, but I'm in favor of advanced sensors. Advanced sensors mean fewer space-time anomalies, more deflector-dish shenanigans, and maybe increased ability to penetrate current-generation cloaks, since we got their sensor profiles. Optimizing for bioscience also makes sense, however.
Man, I'm excited to build a new explorer shortly. Hopefully we can get even more science in since we'll have the new cruiser to handle local engineering support.