The question is about identifying a fixed collocation with the verb 'manage'. 'A. Manage to do' is the correct answer as it is a common collocation meaning to succeed in doing something. 'B. Manage with' implies doing something with limited resources, 'C. Manage on' suggests managing to live on a particular amount of money, and 'D. Manage at' is not a standard collocation with the verb 'manage'.