a. What error does a segfault indicate? [2 pts] b. When you call a C library function (such as fopen) and it fails, what function can you use to print a description of the error? [2 pts] You compile a simple "hello world" program and send the resulting binary, a.out, to a friend. Unfortunately, she says it will not run on her computer, even though you have verified the code is correct. Why could this happen? [4 pts] c. d. List the three phases of compilation and explain what they do. [6 pts]