What is an important problem affecting teenagers today, particularly in the realm of mental health?

a) Academic pressure and high expectations from parents (Source: American Psychological Association, 2020)

b) Cyberbullying and online harassment (Source: National Center for Education Statistics, 2021)

c) Social media influence on body image and self-esteem (Source: Journal of Youth and Adolescence, 2019)

d) Lack of access to mental health resources and stigma surrounding seeking help (Source: National Alliance on Mental Illness, 2022)