A student planning an evidence-based statement about recycled aggregate in concrete recorded these points: Student notes: - Concrete with 10 percent recycled aggregate reached 99 percent of the control mix's strength. - A 30 percent mix reached 92 percent. - A 50 percent mix reached 78 percent under standard curing. - Moist curing raised the 50 percent mix to 86 percent of control strength. - Durability beyond one year was not tested. The student needs an accurate, cautious synthesis of the evidence concerning aggregate proportion, curing, and strength in the tests. Which choice best provides it?