To round up a decimal variable to four decimal places in Microsoft Dynamics 365 Business Central, you should use the Round function with specific parameters. The correct formula is Result := Round (AmountLCY, 0.0001, '=') (B). This function rounds the AmountLCY variable to the nearest value based on the second parameter, which is 0.0001 in this case, representing four decimal places. The third parameter, '=', specifies that the function should round to the nearest value, which effectively rounds up the value when it's halfway between two possible rounded values. This approach ensures that the AmountLCY variable is accurately rounded to four decimal places, which is essential for financial calculations and reporting to maintain precision.