Read the Following Scenario and Answer the Question Below

Read the following scenario and answer the question below.
Despite the high cost of the technology to design genetically modified (GM) crops, American companies have invested in their development. The first genetically engineered crop was the Flavr Savr tomato, which was created by reversing the function of a normal tomato gene. It was approved by the FDA for sale in the United States in 1994. Its grower, the Calgene Corporation, maintained that it would ripen longer on the vine, taste and ship better, and last longer on supermarket shelves compared to conventional tomatoes. It is no longer marketed because of technical problems and public safety concerns.
Today, most engineered crops are modified for insect and herbicide resistance. In 1997, the Monsanto company first marketed GM corn. This Bt corn was engineered using genes from the Bacillus thuringiensis bacteria that made the corn resistant to some pests. In 1999, environmentalists were alarmed when it was reported that pollen from Bt corn could kill monarch butterfly larvae if corn pollen drifted onto milkweed plants that monarchs fed upon. Consumers feared the unknown and were concerned about potential food allergies. Presently, corn, along with soybeans, cotton, and canola dominate the GM food market. These crops are grown and distributed mostly in the United States, Argentina, Canada, Brazil, and China. They are used mostly for animal feed, clothing, or to make oil or other ingredients for processed food, which has helped them gain public acceptance. Although GM crops such as strawberries, potatoes, and lettuce have all been marketed in the United States, GM food field trials involving biotech fruits and vegetables have dropped significantly during the past several years, and the pace of new product introductions has fallen sharply. This narrow range of crops could mean that biotechnology may not realize its full potential in the future.
-Why have most bioengineered crops been modified for ʺresistanceʺ traits?

A) These are the only traits proven safe for the environment.
B) No technology exists to engineer other traits successfully.
C) These traits have the economic potential to save on production costs.
D) These are the only traits proven safe for the human health.
E) Crops with these traits taste better.