A.I. Explanation:

Option 1: "Online purchase of fitness equipment"

Explanation: This option is incorrect because the text does not mention anything about purchasing fitness equipment online. The focus is on the app's features related to workout routines and community engagement, not on selling products.

Option 2: "Social media sharing of workout achievements"

Explanation: This option is incorrect as the text does not reference any social media features. The emphasis is on tracking progress and connecting with trainers, rather than sharing achievements on social platforms.

Option 3: "Personalised dietary plans"

Explanation: This option is incorrect because while the text mentions nutritional tips, it does not specify that these are personalised dietary plans. Thus, it does not fully capture the feature described in the text.

Option 4: "Virtual reality workout environments"

Explanation: This option is correct as the text explicitly states that the latest update includes a virtual reality (VR) mode, allowing users to experience immersive workout environments. This feature is a significant enhancement to the app, aligning perfectly with the question about new features.