Question

Throughout the 20th century, Republicans have done which of the following? Select all that apply.

Answer 1

The answers are: 
had their strongest showing with Ronald Reagan who won all but one state
and 
elected Dwight D Eisenhower- twice

Reagan won every state but Wisconsin in 1984, and Eisenhower was elected twice in the 1950s. 
The Republicans virtually never controlled both Houses and the presidency during the mid-20th century. Remember that FDR set the stage for Democrat dominance for years to come. They also didn't mostly lose to Democrats in landslides- a lot of Republican presidents got elected during this time, such as Eisenhower, Nixon, and Reagan. Also, George H W Bush didn't win his incumbent election, he lost to Clinton in 1992. 

Answer 2

had their strongest showing with Ronald Reagan who won all but one state

elected Dwight D Eisenhower- twice