New Delhi, March 11 -- A QR code on the Class 12 Central Board of Secondary Education (CBSE) mathematics question paper redirects to a YouTube video of English singer Rick Astley's 1987 hit song "Never Gonna Give You Up", triggering confusion even as the board maintained that the security of the question paper remains uncompromised. QR codes are included on board papers for security verification. The exam was held on March 9, and images of the question paper began circulating on social media soon after. htc...