阅读下面短文，从短文后所给的各题的4个选项中，选择最佳选项。
Sometimes I really doubt whether there is love between my parents. Every day they are very busy trying to make money for my schooling.
One day, my mother was sewing a quilt. I silently sat beside her.
"Mom, is there love between you and dad?" I asked in a very low voice.
With surprise in her eyes, he stopped her work for a while. Then she said, "Susan, look at this thread. It can hardly be seen, but it's really there. It makes the quilt strong. If life is quilt, love should be a thread .love is inside."
I couldn't understand her until the next spring. At that time, my father suddenly got sick seriously. My mother had to stay with him in the hospital for a month.
After they were back, my mother helped my father walk slowly on the country road every day .They were so kind to each other and it seemed that they were the happiest couple.
After two months, my father still couldn't walk by himself.
"Dad, how are you feeling now?" I asked him one day.
"Susan, don't worry about me," He said." I just like walking with your mom. I like this kind of life." Reading his eyes, I knew, he loves my mother deeply.
Now I understand that love is just a thread in the quilt of our life. Love is inside, making life strong and warm.