Which of the Following Statements Is Correct

Multiple Choice

Which of the following statements is correct?

A) scientists still think it is necessary to write a Turing machine when they talk about an algorithmic computation
B) a Turing machine that is executing an algorithm to solve some task must halt when begun on a tape containing input appropriate to that task
C) a Turing machine that is executing an algorithm to solve some task need not halt when begun on a tape containing input appropriate to that task
D) just running the Turing machine enables us to decide about halting