Answer: B

The opening modifier "Since the..." indicates that what follows is something that has been happening. Thus, we can expect to see the present perfect tense, as it is in (A), (B), and (D).

(D) can be eliminated due to the "because of largely" at the end. "Largely" should indicate that most of the decrease in innovation is due to certain things, not that the decrease is due to largely technological pressures. (A) can also be eliminated due to the wrong preposition at the end of the underlined portion. "Because of" (in (B)) explains that one thing is the cause of another; "from" is not nearly as clear. Since the causal relationship is what the sentence is getting at, (B) is correct.