Sam was considering purchasing a cell phone. He went to one store and saw two phones for sale. One was selling for $1000, and the other was selling for $1200. The two were the same except that the first one had 126 GB storage and the latter one had 256 GB storage. He was indifferent between the two options and was not sure which one to buy. Then he went to another store and saw the same two phones that he saw in the first store. But this store was also selling another phone that was the same as the other two except it had 512 GB storage and the price was $1700. Sam bought the $1200 phone immediately. Which of the following statements best describes Sam's choice?

a) Sam's choice is rational.

b) Sam's choice violates the transitivity axiom

c) Sam's choice violates the completeness axiom

d) Sam's choice violates the invariance axiom.