Understanding cron scheduling syntax

Which of the following is the correct Crontab syntax for execute the Python model script (model.py) every hour, on the 15 minute of an hour? (e.g. 12:15 PM, 1:15 AM, 2:15 AM, etc)?

Remember the syntax for Crontab:

.---------------- minute (0 - 59)
|  .------------- hour (0 - 23)
|  |  .---------- day of month (1 - 31)
|  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
|  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed ...
|  |  |  |  |
*  *  *  *  * command-to-be-executed

Possible Answers

* * * * * python model.py
15 * * * * python model.py
15 * * * python model.py
15 * * * * model.py

Exercise

Understanding cron scheduling syntax

Instructions

Possible Answers