Which of the following pairs with a Bronsted-Lowry base to form a conjugate acid?

When a Bronsted-Lowry base accepts a proton (H+), it forms a conjugate acid. In this context, a stronger base is more capable of effectively accepting protons compared to weaker bases. When a strong base engages in a reaction with a proton donor (acid), it forms a conjugate acid that is relatively stable and readily produced.

Choosing the strongest base maximizes the ability to accept a proton, thus leading to a more favorable reaction that produces a stable conjugate acid. The stability of the conjugate acid formed can be attributed to the enhanced energy affinity in the stronger base, which effectively stabilizes the additional proton.

In contrast, weaker bases have a reduced capacity to accept protons, resulting in less stable conjugate acids. Strong acids and weak acids' involvement is tangential to the direct mechanism of forming a conjugate acid with a base, as they focus on proton donation rather than the proton acceptance characteristic central to forming conjugate acids with bases.