Explanation:

This question pertains to the classification of keys on a standard computer keyboard. \nOption A: Modifier/मोडीफायर is the correct answer. Ctrl (Control), Shift, and Alt (Alternate) keys are known as modifier keys. Their primary function is to modify the behavior of other keys when pressed in combination. For example, pressing 'Shift' with a letter key produces an uppercase letter, and 'Ctrl + S' typically saves a document. \nOption B: Function/फंक्शन keys are typically labeled F1 through F12 (or F19 on some keyboards) and perform specific tasks that vary depending on the operating system or application. They do not modify the input of other keys in the same way Ctrl, Shift, and Alt do. \nOption C: Alphanumeric/एल्फान्यूमेरिक keys include letters (A-Z) and numbers (0-9), along with some symbols, which are used for typing text and numerical data. They are primary input keys, not modifiers. \nOption D: Adjustment/एडजस्टमेंट keys is not a standard classification for keyboard keys. While some keys might adjust settings (like volume or brightness), Ctrl, Shift, and Alt are not categorized this way. \nTherefore, Ctrl, Shift, and Alt are fundamentally modifier keys due to their role in altering the function of other keys.