Eleanor's nickname as First lady was "Rover" because: It was the name of her favorite dog

She liked to make surprise visits and you never knew where she'd show up

She was a big nature hiker, especially on the Pacific Crest Trail

By October of 1942, Eleanor Roosevelt was on her way to visit a country in the midst of war, where the shrill sounds of air raid sirens and the whistle of German bombs were a part of daily life. Despite the danger, Eleanor Roosevelt was determined to go because she wanted to be doing something useful.  Security and secrecy were essential to ensure the safety of the First Lady. Therefore, her name was not mentioned in official communications.  Instead she was given the  code name “Rover”.  Although the Secret Service assigned her that code name, she suspected that her husband had something to do with the choice.  People who officially accompanied her were dubbed “Rover’s Rangers”.

Explanation: I think She liked to make surprise visits and you never knew where she'd show up

the answer is a. for apex ur welcome