Step 1: Recall the natural history. A cryptorchid (undescended) testis may descend spontaneously during the first few months of life, so surgery is not done at birth.
Step 2: Recall the window for spontaneous descent. Spontaneous descent essentially stops by about 6 months of age; after this, descent is very unlikely.
Step 3: Recall why early orchidopexy matters. An undescended testis left in an abnormal position is at risk of impaired spermatogenesis, infertility, malignancy and torsion, and these risks increase with delay, so the testis should be brought down and fixed early.
Step 4: Apply the guideline. The recommended ideal age for orchidopexy is around 6 months (and is generally completed by 1 to 2 years at the latest), so the earliest correct option here is 6 months.
Step 5: The correct answer is 6 months (option 1).