The question asks about the number of Industrial Area Development Authorities functioning in the state of Jharkhand. This is a factual question related to the development infrastructure in Jharkhand and requires knowing the specific administrative setup of the state's industrial facilities.

As of the current records and the context of the examination on government structures in Indian states, Jharkhand has five Industrial Area Development Authorities. These authorities play a crucial role in facilitating industrial growth by providing necessary infrastructure, planning, and developments in their respective regions.

• Adityapur Industrial Development Authority (AIDA): Located near Jamshedpur, this authority is instrumental in the development of industrial infrastructure in Adityapur, an industrial city.
• Ranchi Industrial Area Development Authority (RIADA): This authority focuses on industrial growth and development in and around the capital city, Ranchi.
• Bokaro Industrial Area Development Authority (BIADA): Bokaro is another key industrial zone, where BIADA is responsible for managing and fostering industrial facilities.
• Santhal Pargana Industrial Area Development Authority (SPIADA): Catering to the Santhal Pargana region, SPIADA manages development plans for industries in this tribal region.
• Dhanbad Industrial Area Development Authority (DIADA): Known primarily for coal mining, Dhanbad is also managed as an industrial zone by DIADA.

Therefore, the correct answer is 5, which matches with the required options. The existence of these five authorities is crucial in managing the diversification and industrial growth in Jharkhand.