Blithe definition
Blithe means light-hearted. It does not mean strong (A), humorous (B) or funny; strange (D), or envious (E).
Blithe means to show casual and cheerful indifference; uncaring. Therefore, "indifference" is the correct synonym for the given word. Thus, option D is correct.
Blithe means to show casual and cheerful indifference; uncaring. Therefore, "indifference"