Please help me understand the following statement:

No party shall serve upon any other party as of right more than thirty interrogatories, including interrogatories subsidiary or incidental to, or dependent upon, other interrogatories, and however the same may be grouped or combined; but the interrogatories may be served in two or more sets, as long as the total number of interrogatories served does not exceed thirty. The court on motion for good cause shown may allow service of additional interrogatories; or the party interrogated, subject to Rule 29, may agree to such service. All interrogatories shall be numbered consecutively.

Which of the following is correct answer to the above statement?
1) one can only ask 30 questions for the interrogatory; and one can ask in two or more times. In another words, the total questions are not more than 30 questions.
2). one can ask many questions every time in the interrogatory, as long as not more than 30 times.
3). other possible interpretation

Thanks in advance for your help.