You are implementing patient education for a client who has just started taking levothyroxine (Synthroid) for their hypothyroidism. Which of the following statements made by the client requires further instruction?

a. "I should only use one brand and use the same one every time when taking this medication because not every brand has the identical effect."
b. "This medication should only take a week for an effect to take place."
c. "I should recheck my thyroid hormone levels one month after beginning levothyroxine."
d. "I should take this medication 30-60 minutes before breakfast."