In this task, you're given an article and an answer. Your task is to generate the question for the answer based on the given article.

Article: Following Christmas dinner,my family was relaxing around the kitchen table.The goodcooking smells still stayed.My sister,our chef, was enjoying the compliments."Delicious meal!""Everything was wonderful."Dad had risen from his chair and was contentedly standing nearby. My nephew,never one to sit still for too long,began playing his new basketball around the table and throughout the kitchen.Upon nearing Dad,he stopped----almost uncertainly.With shaking,wrinkled hands,Dad had reached out for the ball.He did not speak,and the boy,confused,looked up and over at us.It took some convincing,but the ball was lightly passedover. I watched my father closely to see what he would do.A playful smile appeared on his face.Holding the ball and reaching forward,Dad bounced it on the floor then caught it.This action was repeated.Nodding approvingly,he then turned towards our assembled group.Gently throwing the ball away,Dad began a game of catch. The ball continued to be passed though eager pairs of outstretched hands.Cries of"Over here!"rang through the warm kitchen.Dad's active participation in this game was remarkable to me,since he had advanced Alzheimer's disease.This disease had robbed him of many memories and the recognition of people,places mid points in time. In my younger years,playing with Dad was rare.To his credit,Dad worked hard and provided for us.He was very private and never showed nor shared much emotion.His game of choice was chess,which he did eventually teach me how to play.As an adult,I had become a caregiver and watched helplessly as Dad declined.Connecting moments between father and son had been few and far before he took the basketball. I'm not sure how long we played catch.What I do know is that our game ended all too soon,and it was time to face the reality of dirty dishes piled high on countertops.The moment,though,will certainly last forever.On this Christmas,Dad gave me a special memory--one that I will always treasure.
Answer: Amazed.
How did the author feel on his father's active participation?