Your "setup", with the CEO and various students was PHENOMENAL! The answers are B and D: purchased, not "perchased", and excuse, not "excuce". However, I believe there is also a grammatical mistake. I learned (USA) that words such as "class", "couple", "group", "neither", etc., require extra thinking because it must be decided if the word, in context, is referring to the noun collectively, or as individuals. "Parents" would normally need the 3rd person plural, "were". However, the sentence is, I think, stressing that as individuals, NEITHER believed me. So, in my class we would have used "was" for this sentence. I don't know if that is correct. I am 73 and have noticed that, at least here in the States, grammar is VERY poor, often regardless of educational level. For example, I never see s/he used to refer back to a person. I see and hear, "A person who doubts THEIR spelling skills should read and practice." I learned that "person" should require the third person SINGULAR, "his" or "hers".
Great first answer - check the second one again. I bet you can spot it using our strategy of isolating each word, one at a time working backwards from the end of the sentence.
