This directly calls out a major assumption in the argument: that Barajas did not regularly deviate from her sketches. This majorly weakens the main conclusion of the argument.

This does not impact the argument’s reasoning. The three assistants who made the statue could have also worked closely with Barajas

It is unclear whether these materials would impact the statue's appearance. Thus, it is too weak to cast doubt on the conclusion

This does not say whether the sketches were indicative of the final version of the statue. This is too nonspecific to support

The time it takes to create the statue does not impact how it looks, which is what the reasoning and main conclusion are focused on.