Which Android user-agent category corresponds to rv values of 40.0 and Firefox 40.0?

• A. Android User-Agents (version 40 and below)
• B. Android User-Agents (version 41 and above)
• C. Android 4.4 devices
• D. Tablet Category

Answer: (A)

rv in a user-agent string signals the Gecko/Firefox rendering engine version. An rv value of 40.0 corresponds to Firefox 40.0, which sits in the Android User-Agents category for version 40 and below. The 41+ bucket would apply to rv 41.0 and Firefox 41.0 and above. The Android 4.4 devices option targets the Android OS version rather than the browser engine version, and the Tablet Category is about device form factor, not the engine version. So the best match for rv 40.0 and Firefox 40.0 is the Android User-Agents category for version 40 and below.