Here are the ones that have that rule:
Alabama, Arkansas, Georgia, Oklahoma, Texas, and Vermont
It’s an outside chance, but Cruz could do it in is Texas.
I can see Trump pulling over 50% in some of the others...depending on what happens between now and then.
You may see Christi, Fiorinia, Kasich and carson all drop out between now and then.
The Texas rules are a little more complicated than that:
108 district delegates are to be allocated to presidential contenders based on the primary results in each of the 36 congressional districts: each congressional district is assigned 3 National Convention delegates. These delegates are allocated to the presidential contenders as follows:
If a candidate receives a majority of the vote (more than 50%), that candidate is allocated all 3 of the district's delegates. [General Rules for All Conventions and Meetings. Rule 38. Section 8.a. and 8.b.]
If no candidate receives a majority of the vote and at least 1 candidate receives 20% or more of the vote, the candidate with the most votes (plurality) receives 2 delegates and the candidate receiving the next highest number of votes receives 1 delegate. [Rule 38. Section 8.b.]
If no candidate receives 20% of the vote then the top 3 vote getters each receive 1 delegate. [Rule 38. Section 8.c.]
47 at-large delegates (10 base at-large delegates plus 34 bonus delegates plus 3 RNC delegates) are to be allocated to the presidential contenders based on the primary results statewide. These delegates are allocated to the presidential contenders as follows:
If a candidate receives a majority of the vote (more than 50%) that candidate is allocated all 47 at-large delegates. [Rule 38. Section 9.a. and 9.b.]
If no candidate receives a majority of the vote and at least 2 candidates receive 20% or more of the vote, the 47 at-large delegates are allocated proportionally among those candidates receiving 20% or more of the vote. Rounding rules: Beginning with the candidate receiving the largest number of votes, round any fraction to the next whole number of delegates. Continue this process with the next highest vote getter and repeat until all the delegates are allocated. [Rule 38. Section 9.b.]
If no candidate receives a majority of the vote and only 1 candidate receives 20% or more of the vote, the 47 at-large delegates are allocated proportionally between the candidate receiving 20% or more of the vote and the candidate receiving the next highest number of votes. Rounding rules: Beginning with the candidate receiving the largest number of votes, round any fraction to the next whole number of delegates. Continue this process with the next highest vote getter and repeat until all the delegates are allocated. [Rule 38. Section 9.b.]
If no candidate receives 20% of the vote, allocate the 47 at-large delegates proportionally. Rounding rules: Beginning with the candidate receiving the largest number of votes, round any fraction to the next whole number of delegates. Continue this process with the next highest vote getter and repeat until all the delegates are allocated. [Rule 38. Section 9.c.]