Which among the following factors cause Turner's syndrome?

The correct option is D (b) and (c) above.
Turner's syndrome arises due to abnormalities in sex chromosomes. The factors leading to Turner's syndrome are:

• Inheritance of only one X chromosome from parents.
• Inactivation of gender-related part of X-chromosome.

Instead of the normal 44+XX chromosomal condition, women suffering from Turner's syndrome show 44+XO condition. They are sterile, i.e., they are unable to have children due to improper growth of their reproductive organs.