Botswana and Namibia are countries in Africa specializing in mining gems. Suppose Botswana can mine $100$ carats of diamonds or $200$ rubies in one day, while Namibia can mine $120$ carats of diamonds or $80$ rubies in one day. The opportunity cost of one diamond is in

Botswana and in Namibia.

$0\mathrm{.}5$;$0\mathrm{.}67$

$2\mathrm{.}0$;$1\mathrm{.}5$

$0\mathrm{.}5$;$1\mathrm{.}5$

$2\mathrm{.}0$;$0\mathrm{.}67$