"A character sketch is a description made for the purpose of guiding the writer on such assignments as introducing a particular character to the reader in such a way that both the writer and readers can have a quick overview of the character's attributes; including but not limited to physical appearance, idiosyncratic (individual) tendencies in different circumstances, state of mind as shaped by former experiences and how these will affect their future actions."
Option D: As mentioned above, a character can be portrayed best by describing how they think and feel 'state of mind as shaped by former experiences'. The writer describes the character so that the reader can understand it better. The understanding will come through when the reader identifies with the thoughts and emotions of the character. Hence option D is correct.
Options A, B and C:
The date of birth, parents' names and 'hair colour' do not describe the character in its best possible way. It does not help the reader understand the character.
Hence these options are wrong.