Answer: E. however
The transition word best suited to connect the clauses is “However”
Transition words and phrases are vital tools in communication. They help to link clauses to establish coherence within a discuss; hence, making it more interesting. Transitional words and phrases can express agreement (e.g., likewise), contradiction (e.g., nevertheless), cause (e.g., with this in mind), emphasis (e.g., that is to say), effect (e.g., therefore), conclusion (e.g., in essence), sequence (e.g., henceforth) and location (e.g., nearby)
“However,” is used to express contradiction and in the question, the clauses were contradictive.