Answer:
Watching two half-hour TV sitcoms
Step-by-step explanation:
Opportunity cost is the cost of best opportunity foregone while choosing the current opportunity.
As for studying economics the next best activity could be watching 2 TV sitcoms each of half hour making a total of 1 hour. That is equivalent to time taken for studying economics.
As all opportunities are laid in the next best manner, thus, the cost of study economics is the opportunity foregone of watching TV.