IS IT A OR C IM CONFUSED WILL GIVE BRAINLIEST FOR CORRECT ANSWER

Read the following sentences.

Flash mobs seem both interesting and safe. Participants are irresponsible.

Which of the following correctly combines these two sentences into a complex sentence?

A.
Flash mobs seem both interesting and safe, unless participants are irresponsible.
B.
Flash mobs seem both interesting and safe, but participants are irresponsible.
C.
Flash mobs seem both interesting and safe, yet participants are irresponsible.
D.
Flash mobs seem both interesting and safe, participants are irresponsible.