Answer: Indirect form-- The principal will say that Rules had to be followed at any cost.
Step-by-step explanation:
A direct form of speech indicates exactly what the speaker says that is the original words from the speaker . To indicate it easily, it is usually in quotation marks so that one can know the quoted text is in the speaker's own words.
An indirect form of speech also known as reported speech shows when the speaker's statement s being reported by another person without any change in the meaning of the statement.
From the given question
The principal will say, ’rules have to be followed at any cost
Direct form --The principal will say, ’rules have to be followed at any cost
Indirect form-- The principal will say that Rules had to be followed at any cost.