A Zambian firm has one million Kwacha to use for investment either at home or abroad (in either South Africa or Botswana) for a period of six months. Suppose the interest rate on the Zambian Treasury bill is 12 percent per year. The interest rate on the South African Treasury bill is 14 percent per year. The interest rate on the Botswana Treasury bill is 15 percent per year. The Rand is at a forward discount of 2.5 percent per year with respect to Kwacha. The Pula is at a forward discount of 4 percent per year with respect to the Kwacha. Advise the firm where they should invest.