Why were Harry's Hogwarts Acceptance Letters Not Sent Directly To Him?

In Harry Potter and the philosophers stone Harry was "receiving" his letters in a way that was so labour intensive. First, one was sent in the mail, and the others where then sent, either shoved into the letterbox or through the door cracks. It then it got, "out of hand," as twenty four letters found their way inside the house. The letter sender (Minerva, I do believe, Deputy Headmistress) must, obviously have known they were not getting to Harry, so why keep sending them? I cannot even believe Minerva sending more than thirty letters! Why not either,

A) Send the letters directly to Harry

OR

B) Show up at the house, to explain everything.

Why not do a more logical way of sending/explaining Harry's being?