Comprehensive and Detailed Explanation From Exact Extract:
Authenticator apps (e.g., Microsoft Authenticator, Google Authenticator, Duo) often support push notifications. When the user logs in, the app sends a push to their mobile device, prompting the user to approve or deny the authentication request - a common and user-friendly form of multi-factor authentication (MFA).
A). Phone call verification is a separate method involving voice-based confirmation.
C). Hardware tokens generate one-time codes but do not send push notifications.
D). SMS sends a text message with a code - again, no push mechanism.
Reference:
CompTIA A+ 220-1102 Objective 2.2: Compare and contrast multi-factor authentication methods.
Study Guide Section: Authentication apps and push notification verification