Question: OG 12

In option D of the question OG. 12, it said "apply to them". Does this pronoun "them" have ambiguity?  I think this word “them” can refer to  the “small new business” or “formula”. How could we judge whether a pronoun is ambiguous or not?

12. Formulas for cash flow and the ratio of debt to equity do not apply to new small businesses in the same way as they do to established big businesses, because they are growing and are seldom in equilibrium.

(D)  Because new small businesses are growing and are seldom in equilibrium, formulas for cash flow and the ratio of debt to equity do not apply to them in the same way as to established big businesses.

Do you mean that if we can figure out the pronoun reference from the logical meaning, there is no pronoun ambiguity? But in some cases, OG said there is a pronoun ambiguity, I can easily figure out to which the pronoun wants to refer from the logical meaning of the sentence. Is there any rule we can follow to recognize this thin line?

         pronoun

        1. no logic reference(has no antecedent / not match in number)------>wrong

        2. has logic reference----->suppose it is right and search other errors(compare this choice with others)

        note: you are asked to give a best choice, if one choice has just a puzzled pronoun and the others have errors, why not the former choice???

        puzzle or confusion means that it may be right or wrong