Choice "B" is correct. To fix a price in dollars to buy British pounds, British pound call options should be purchased. Call options would allow, but not require, the purchaser of the call to acquire the currency (British pounds) for a specified price at or before a specified time in the future. If the price goes up, the purchaser (the importer) would exercise the options; if not, the purchaser (importer) would buy the British pounds in the market and let the options expire. British pound futures could also be used, but that was not one of the choices listed.
Choice "c" is incorrect. Buying British pound put options would allow, but not require, the purchaser of the put to sell the currency for a specified price at a specified time in the future. Since the importer needs British pounds, buying put options would not work. The importer needs to end up with British pounds.
Choice "a" is incorrect. Selling British pound put options would not work. The importer needs to end up with British pounds. Selling put options could work, but the option would be exercised, or not, by the purchaser and not by the importer. If the options were not exercised, the importer could end up with nothing (other than the option premium).
Choice "d" is incorrect. Selling British pound call options would not work. The importer needs to end up with British pounds; if call options are sold, the other party can exercise the options or let them expire, and if the options were exercised, the importer would have to supply the British pounds. This answer is backwards.