Which of the following Special Program Indicators (SPI) is NOT valid?
How to get there
General Note 3(c)(i) lists every program symbol that can appear in the "Special" rate column. The relevant entries:
HTSUS General Note 3(c)(i) (excerpt)B: Automotive Products Trade Act · BH: U.S.–Bahrain FTA · P or P+: Dominican Republic–Central America–U.S. FTA (CAFTA-DR) · S or S+: United States–Mexico–Canada Agreement · … (no "BU")
BU isn't on the list. The answer is A.
Why the other choices are wrong (they're all valid)
B) S and C) S+: both are listed for USMCA.
D) P: listed (with P+) for CAFTA-DR.
Trap!
"BU" looks plausible next to real two-letter codes like BH (Bahrain) and the one-letter B (Automotive Products Trade Act). On exam day, check General Note 3(c)(i) instead of trusting what looks familiar.
Source: HTSUS General Note 3(c)(i) (USITC HTS, General Notes).
CBP answer key: Answer A · HTSUS General Note 3(c)(i)Source: CBP past exams ↗