Explanation
Correct answer: C.
Choice C is the best answer. "In fact" logically signals that the information in this sentence about the creation of the video game offers additional emphasis in support of the previous claim that video game studio founders Koola and Viv love cats.
Why the other choices are wrong
Choice A
Choice A is incorrect because "intermittently" illogically signals that the information in this sentence occurs sporadically or in intervals. Instead, the creation of the video game offers additional emphasis in support of the previous claim about Koola and Viv.
Choice B
Choice B is incorrect because "on the other hand" illogically signals that the information in this sentence contrasts with the previous claim about Koola and Viv. Instead, the creation of the video game offers additional emphasis in support of that claim.
Choice D
Choice D is incorrect because "nevertheless" illogically signals that the information in this sentence is true despite the previous claim that Koola and Viv love cats. Instead, the creation of the video game offers additional emphasis in support of that claim.