Question 2.4 is asking you to distinguish between relative price and absolute price. The definition you have quoted from page 34 is the definition of absolute price. But, look at the bold statement near the top of page 35: "In microeconomics the single word price always refers to the relative price." So, in question 2.4, when they ask us what Landsburg means by "the price of bread," you can insert the word "relative" before "price." Now you have question 2.4 reading as "When Landsburg says the relative price of bread is $1.50 per loaf..." Then if you read the section entitled "Relative Prices When There Are More than Two Goods" on page 35, you will find that the best answer to question 2.4 is A, as stated.

Regarding question that asks "When Landsburg says the price of bread is $1.50 per loaf...."

On p. 34 of Landsburg, it says "The number of dollars necessary to purchase [a good] is called the absolute price of [the good]." Seems like this implies the answer is C. Why is C incorrect?

Thanks