Final Answer:
Mrs. Figg said she was going to kill Mundugus Fletcher after he c) Betraying Harry Potter's whereabouts
Step-by-step explanation:
In the Harry Potter series, Mundungus Fletcher is reprimanded by Mrs. Figg for betraying Harry Potter's whereabouts. Mundungus, known for his shady dealings, was entrusted with ensuring Harry's safety by keeping an eye on him. However, he failed in this responsibility by revealing crucial information about Harry's location, much to Mrs. Figg's dismay and anger. This act of betrayal put Harry's safety at risk, prompting Mrs. Figg's strong reaction. The correct answer is C.