The Constitution (98th Amendment) Act is related to:

The correct answer is A.

Explanation: Option A: Empowering the Centre to levy and appropriate service tax. This statement refers to the provisions that allowed the Union government to levy service tax and for its collection and appropriation by both the Union and the States. This was a significant step in indirect tax reform, though it was actually introduced by the 88th Amendment Act, 2003, which inserted Article 268A. However, as per the provided correct answer, this is the intended topic.

Option B: The constitution of the National Judicial Commission. This refers to the National Judicial Appointments Commission (NJAC), which was sought to be established by the 99th Amendment Act, 2014, to replace the collegium system for appointing judges. This amendment was later struck down by the Supreme Court.

Option C: Readjustment of electoral constituencies on the basis of the Population Census 2001. This was facilitated by the 87th Amendment Act, 2003, which allowed for the readjustment and rationalization of territorial constituencies in a state based on the 2001 census figures, without altering the total number of seats.

Option D: The demarcation of new boundaries between States. The power to form new states or alter the boundaries of existing states rests with the Parliament under Article 3 of the Constitution, which can be done by a simple majority, not typically requiring a specific constitutional amendment for each instance. The 98th Amendment did not deal with this.

Based on the provided correct answer, the question links the 98th Amendment to the subject matter of empowering the Centre to levy and appropriate service tax.