They had problems with trade because of the unstable government so they couldnt make "money" as easily
According to Albert Barnes, their mistake was that they didn't speak against slavery. Although many of them believed that slavery was against god and against the idea that god made everyone equal, they didn't do much against it out of many reasons, either they thought it was a necessary evil or they were afraid of the public reaction.
The correct answer is B. Giving to charity
A and B are incorrect because they're not part of the 5 pillars. Finding ways to help other who are not as lucky as you is. Living in Mecca is not one of the pillars, but traveling to Mecca at least once in a lifetime is.
A. Primary Sources are raw materials of time, original documents created at that time.