While appeared in movies and as a guest on popular television shows in the second half of the twentieth century, her musical collaborations with louis armstrong, duke ellington, and the ink spots were some of her most notable acts outside of her solo career.

Ella Fitzgerald

Explanation:

While Ella Fitzgerald appeared in movies and as a guest on popular television shows in the second half of the twentieth century, her musical collaborations with Louis Armstrong, Duke Ellington, and The Ink Spots were some of her most notable acts outside of her solo career.

d is the best answer for this question.

the answer to fill in the blank in this question would be the word resource, it is defined as the money, material or people (since human resource is a very valuable good) that a company or a person has at disposition (meaning they can use the resource as they see fit), to be able to complete a task or achieve a goal.