The pilot program was designed to test whether small classroom sizes alone could improve reading scores, holding every other variable,…

The passage describes a deliberately controlled test isolating one variable, and the second sentence reports the outcome that emerged from that specific design, a natural consequence of removing other explanatory factors. As a result correctly frames the marginal improvement as the finding that followed from this controlled setup. Meanwhile would suggest simultaneous but unconnected events, not a designed test producing a result. Nonetheless would suggest the outcome happened despite some obstacle or expectation stated in the first sentence, but the first sentence describes a method, not a competing expectation. Likewise would incorrectly suggest the second sentence echoes the first instead of reporting what the described method actually found.