Which of the following statements about bioengineered foods is false?
a. their dna has been modified.
b. they have been genetically modified.
c. they were developed during the green revolution.
d. genetic material from another organisms is sometimes added

The bioengineered food products are those food products, which are modified by the alteration in their genetic material. There alteration in the genetic material is done by changing and incorporating the gene of interest in the DNA of the organism. Sometimes, the gene of interest are derived from the genome of the other organisms.

The use of the chemical pesticides escalated the green revolution, at that time  the genetically modified food product were not so developed.

Hence, the correct answer is c. They were developed during the Green Revolution.