In which of the following situations can WACC NOT be used as the discount rate?

Multiple Choice $($one answer only$)$

Firm X$,$ a xylophone producer, wants to enter into the guitars industry.

Firm V$,$ a producer of vending machines, is planning to expand its current manufacturing facilities for vending machines.

Firm Y$,$ which produces yams and taros, would like to abandon yams and focuses on taros.

Firm W$,$ a wind turbine manufacturer, is investigating the possibility of expansion into the production of wheels.

Firm Z$,$ which manages zoos, would like to look into the option of leasing pandas from China.