Concept:The conduct of the new converts after Pentecost reveals their immediate commitment to the apostles' instruction and Christian fellowship.
Explanation:After Peter's post-Pentecost sermon, about three thousand souls were baptized and added to the Church on that day.
Immediately after this baptism, the Bible states that the converts devoted themselves to the apostles' teaching and fellowship.
This event is recorded in Acts 2:42, which also mentions the breaking of bread and prayers as part of their shared life.
Option A therefore describes the exact response of the converts following their baptism.
Option B is incorrect because the early Church did not face disciplinary problems from these converts at this stage.
Option C is incorrect because the deacons were appointed later, after a complaint arose in Acts 6.
Option D refers to the voluntary sharing of possessions recorded in Acts 2:44–45, but the primary consequence highlighted in the passage is their devotion to teaching and fellowship.
Thus, the most direct and scripturally supported answer is option A.
Answer:A. Devoted themselves to the apostles' teaching and fellowship.