Local variables: a. lose the values stored in them between calls to the method in which the variable is declared
b. may have the same name as local variables in other methods
c. are hidden from other methods
d. all of the above

All of the above

Explanation:

A local variable is a variable which is declared within a method or is an argument passed to a method, it scope is usually local (i.e. it is hidden from other method). it can also have the same name as a local variable in another method and it loses the values stored in them between calls to the method in which the variable is declared. So all the option listed above are correct.  

the major difference between the two is the objective and the reward of the game. candy crush has a puzzle theme with the objective of meeting a specific quota of points or objects, you are able to gain access to the next level and compete with peers on the process. on duolingo the objective is rather different, you are given sets of questions for you to answer for you to move to the next level and as for the reward, you are able to learn available language as this is an app developed to teach the user about other languages.