If the officer dictates 'Memorial Day is in May,' which is correct?

Correct: 'Memorial Day is in May.' Capitalization rules: (1) CAPITALIZE the first letter of the sentence: 'M' in Memorial; (2) CAPITALIZE proper nouns and proper adjectives — 'Memorial Day' (a holiday name, both words capitalized) and 'May' (a month, capitalized); (3) DO NOT capitalize: common words like 'is,' 'in,' 'the,' 'a,' etc. (in the middle of a sentence — they would only be capitalized at the start of a sentence). HOLIDAYS on the writing vocabulary list (all should be capitalized when written): COLUMBUS DAY; FATHERS DAY (or Father's Day with apostrophe); FLAG DAY; INDEPENDENCE DAY; LABOR DAY; MEMORIAL DAY; MOTHERS DAY (or Mother's Day with apostrophe); PRESIDENTS DAY (or President's Day); THANKSGIVING. MONTHS on the writing list (all capitalized): JANUARY through DECEMBER. SAMPLE SENTENCES — when you encounter these on the writing test, capitalize properly: 'Memorial Day is in May.' 'Labor Day is in September.' 'Columbus Day is in October.' 'Flag Day is in June.' 'Independence Day is in July.' 'Thanksgiving is in November.' 'Presidents Day is in February.' PERIOD AT END: every dictated sentence should end with a period (.) — or a question mark (?) if it's a question, though most USCIS writing sentences are statements. EXCLAMATION POINTS are not used on USCIS sentences.