Answer:
C) {S, FS, FFS, FFF}
Step-by-step explanation:
The person entering the code needs a success to access the cell phone or the person stops trying when he has failed at all 3 attempts. The possible outcomes are;
(1) The person is successful at first attempt {S}
(2) The person failed at first attempt, successful at second attempt {FS}
(3) The person failed at first and second attempts, successful at third attempt {FFS}
(4) The person failed at the three attempts {FFF}
The sample space is {S, FS, FFS, FFF}