Correct Answer:
A parameter-manipulation attack attempt is correct.
Parameter tampering or parameter manipulation (aka URL tampering) is an attack where the hacker searches a URL string for parameters that can be adjusted. These entries are then manipulated within the URL string in hopes of modifying data, such as permissions and elevation of privilege, prices and quantities of goods, and credentials. On your exam, this will show when an attacker simply changes some of the entries on the URL itself, and will most often be a price or an account. In this example, it appears the attacker may be attempting to change a price.
Incorrect Answers:
A cross-site scripting attack attempt, a SQL injection attempt, and a directory traversal attempt are incorrect.
There is no indication of cross-site scripting (which would be inside the form, anyway) or SQL injection (no query language).
No directory traversal appears either (the dot-slash would be a giveaway).