After the war ended, the economy skyrocketed, making it possible for people to spend more time and money on leisure activities. What are three major innovations that came out of the World War I experience?

the answer would either be a or d

i hope this

in the following paragraph, the fourth sentence the correct answer is: three personal subject pronouns

”she was embarrassed when she found that they had been put back on the shelves…”

a   subject pronoun is a personal pronoun. i, you, he, she it, we, they.  

in the sentence it can be observed she, used twice and they used once. is for this reason that is a three personal subject pronoun sentence.