The chief of builders blamed the workmen for the issue at hand. Here's an explanation of this answer:

Introduction:
The chief of builders, who is in charge of overseeing the construction project, is assigning blame for a problem that has occurred. Let's analyze the options to understand why the chief of builders blamed the workmen.

Analysis of Options:

a) The public:
Blaming the public would not make sense in this context as the public is typically not involved in the construction process. The public may have certain expectations or demands, but they are not responsible for the actual construction work.

b) The architect:
While the architect plays a crucial role in designing the building, blaming them might not be justified unless there was a clear mistake or error in the design that directly caused the problem. However, the question does not provide any information about such a mistake, so blaming the architect seems unlikely.

c) The masons:
The masons are skilled workers who specialize in building structures with bricks, stones, or concrete blocks. While they have an important role in the construction process, blaming them alone would not be reasonable unless there was evidence of their negligence or incompetence. However, the question does not provide any such information.

d) The workmen:
The term "workmen" is a general term that refers to all the laborers and workers involved in the construction project. This includes not only the masons but also other workers like carpenters, electricians, plumbers, etc. Blaming the workmen suggests that the chief of builders believes that the problem occurred due to the collective actions or lack of skills of the workmen.

Conclusion:
Based on the options provided, the chief of builders blamed the workmen for the issue at hand. While the question does not provide specific details about the problem, it can be inferred that the chief of builders believes that the workmen are responsible for the problem due to their actions or lack of skills. However, it's important to note that without further context or information, it is difficult to determine the exact reason for the blame.