Which one is incorrect? B1*B2, 10+17, B1*17, None of these

Which one is incorrect? B1B2, 10+17, B117, None of these

B1*B2

10+17

B1*17

None of these

B1*17 is incorrect because it mixes a cell reference (B1) with a direct number (17) in an improper way for a formula.

Correct formulas should maintain consistent use of cell references or operators.