This is a premeditated murder; the main character plans the old man’s demise. to avoid suspicion, the narrator explains, "i was never to the old man than during the whole week before i killed him."

Premeditated Murder:

"A pre-planned and structured form of murder case, which is then willfully performed  by the accused."

Explanation:

As the accused confesses about his crime of killing an old man. And we are supposed to place the right words in the blank, so we can complete the sentence. After placing the correct word we will have the following answer to it, which is given below as;

"I was never kinder to the old man than during the whole week before I killed him."

c- companies fail to take environmental protection into account. i think