An 80-year-old man was sitting on the sofa in his house along with his 45-year-old highly educated son. Suddenly a crow perched on their window. The father asked his son, "What is this?" The son replied, "It is a crow." After a few minutes, the father asked his son the 2 time, "What is this?" The son said, "Father, I have just now told you 'It's a crow'." After a little while, the old father again asked his son the 3 time, "What is this?" At this time some expression of was felt in the son's tone when he said to his father. "It's a crow, a crow, a crow." A little after, the father again asked his son the 4 time, "What is this?" This time the son shouted at his father, "Why do you keep asking me the same question again and again, although I have told you so many times 'IT IS A CROW'. Are you not able to understand this?" A little later the father went to his room and came back with an old tattered diary, which he had maintained since his son was born. On opening a page, he asked his son to read that page. When the son read it, the following words were written in the diary: "Today my little son aged three was sitting with me on the sofa, when a crow was sitting on the window. My son asked me 23 times what it was, and I replied to him all 23 times that it was a crow. I hugged him lovingly each time he asked me the same question again and again for 23 times. I did not at all feel irritated, I rather felt affection for my innocent child." The reason why the father did not feel irritated when his son asked him the same question for 23 times is that    _   .
he knew his son was still so innocent the father was more patient than the son the father had already got used to this kind of situation the father loved his son so much that he never got tired of doing this again and again