Using it's concept, the sample space for the experiment is:
The sample space is the set that contains all possible outcomes for an experiment.
In this problem:
Hence, considering the combinations, the sample space is, considering Shirt-Pants-Shoes:
{Blue-Blue-Black, Blue-Blue-Blue, Blue-Black-Black, Blue-Black-Blue, Red-Blue-Black, Red-Blue-Blue, Red-Black-Black, Red-Black-Blue, Black-Blue-Black, Black-Blue-Blue, Black-Black-Black, Black-Black-Blue}
The complement of P(John wears something red) is all outcomes in which he does not wear anything red, hence it is a Blue or Black shirt, along with any combination for the pants and the shoes.
You can learn more about sample space at https://brainly.com/question/25861936