单选题Directions: Read the texts that follow. A word or phrase is
missing in some of the sentences. Four answer choices are given below each of
the sentences. Select the best answer to complete the sentence. There is no better way to ______ water resources economically
than to invest in a 'timed mobile sprinkler system' for the farm, park, or
garden. Most communities water their parks manually. This can be very
inefficient and wasteful. A timed mobile system, on the other hand, will ______
apply the proper amount of water to every corner of the park or farm the first
time around. This will save both time and money. There are
several companies that offer this type of product. Gardentools Ltd. has the GT
Mobile water system, which has remote programmability via the Internet. This
system retails for $4,000. The Coolshot from Watertank Ltd. is somewhat less
expensive at $2,500, ______ has much less programmability than the GT
Mobile.