A 6-month-old male infant presents to the pediatric clinic with a soft, bulging swelling at the umbilicus that protrudes when the infant cries and reduces easily with gentle pressure. The mother is concerned about the appearance. On examination, the defect marked **D** in the diagram is identified as a 0.8 cm defect in the linea alba at the umbilicus. Which of the following is the most appropriate management strategy for this infant?