ANSWER: I believe the answer is B, but I'm not sure.
•I was thrilled that my cousin was coming to stay with us. (B. joyous)
Definition: joyous is an adjective which describes the state of great happiness.
•My heart broke when I saw the children in the hospital. (D. empathetic)
Definition: empathy is a psychological identification, ability to share and understand the feelings of others.
•You're so silly, you can't wear pajamas to school. (C. Playful)
Definition: playful expression is expressed with the intent of amusement in contrary to express seriously.
•She has no talent; she's a fool if she thinks she'll be cast in the play. (A. cruel)
Definition: cruel is an expression of being unkind or cold hearted towards other’s pain or suffering.
If you’re trying to rewrite the sentence than B would work best
Answer:
D: since GMO's are fairly new into the Humans technology spectrum, we haven't had much time to test on it and experiment.
Explanation: Hopefully this helps