How many scenarios can Scenario Manager manage?

Which of the following statements is false?

a. A LineNumberReader is a buffered character stream that tracks the number of lines read. b. Classes FileReader and FileWriter perform character-based file I/O. c. Class PipedReader and class PipedWriter implement piped-character streams for transferring data between threads. d. Class StringReader and StringWriter read characters from and write characters to Streams, respectively.

What does it mean when a variable overrides another variable? 

What will be an ideal response?