The correct answer is: A. So, as
The sentence “The more you earn, the more you can spend” is an example of a proportional relationship. In a proportional relationship, there is a direct relationship between two quantities, such that an increase in one quantity results in a corresponding increase in the other quantity. In this case, the two quantities are the amount of money you earn and the amount of money you can spend.
The word “so” is used to introduce a result or consequence. In this case, the result of earning more money is that you can spend more money. The word “as” is used to introduce a comparison. In this case, the comparison is between the amount of money you earn and the amount of money you can spend.
The other options are incorrect because they do not accurately reflect the relationship between the two quantities. Option B, “As, as,” does not indicate a direct relationship. Option C, “The, the,” does not indicate a proportional relationship. Option D, “If, than,” does not indicate a cause-and-effect relationship.