Read the excerpt from Robert Frost's poem "Mending Wall."

He only says, "Good fences make good neighbours."
Spring is the mischief in me, and I wonder
If I could put a notion in his head:
"Why do they make good neighbours? Isn’t it
Where there are cows? But here there are no cows.
Before I built a wall I’d ask to know
What I was walling in or walling out,
And to whom I was like to give offence.
Something there is that doesn’t love a wall,
That wants it down." I could say "Elves" to him,
But it’s not elves exactly, and I’d rather
He said it for himself. I see him there
Bringing a stone grasped firmly by the top
In each hand, like an old-stone savage armed.
He moves in darkness as it seems to me,
Not of woods only and the shade of trees.
He will not go behind his father’s saying,
And he like having thought of it so well
He says again, "Good fences make good neighbours."

What does the word grasped connote in this poem?

that the man is determined to protect himself
that the man knows how to build a wall
that the man can pick up big rocks
that the man is going to attack the speaker