What 2010 NFL rule change, intended to improve player safety, prohibits a defender from launching himself into a defenceless receiver above the shoulders?

• A Helmet-to-helmet rule ✓
• B Targeting rule
• C Roughing the passer
• D Defenceless receiver rule

The NFL has progressively strengthened rules protecting defenceless players from hits to the head and neck area, especially after growing concussion research.