Which of the following characters are used to open a HubL statement?

The correct answer is {%. This character sequence is used to open a HubL statement, which executes logic such as loops, conditional statements, or variable assignments within your HubSpot templates. For example, {% if user.isloggedin %} starts a conditional block. The other options are incorrect: {- is not a valid HubL opening character for statements; it's sometimes used for whitespace control in conjunction with other delimiters. [& is not a recognized HubL syntax for opening any type of block or statement. { is used to open a HubL comment block, not a statement. Comments are ignored by the HubL parser and are used for developer notes.