What are three challenges employers face when using foreign service premiums?

All of the above

employees may misconstrue this premium as a regular permanent increase to base pay, and resentment toward the employer may develop following the last installment

employees may feel as if their standard of living has declined when they return to the United States because they no longer receive this extra money

foreign service premiums may not have incentive value when employers make several small installments rather than fewer large installments