In the hierarchy of urban planning documents, different plans operate at different scales and levels of detail.
(w) (a) Long-term comprehensive plan (or Perspective Plan): This is a high-level strategic document for a large region or city, setting out broad goals and policies over a long time horizon (e.g., 20-30 years). It does not provide detailed guidelines for specific zones.
(x) (b) Structural development plan (or Structure Plan): This type of plan outlines the broad spatial structure of development for an area, including key infrastructure, land use patterns, and major development zones. It is more strategic than detailed for specific zones.
(y) (c) Zonal plan (or Zonal Development Plan, Local Area Plan, Sector Plan): This is a detailed plan prepared for specific zones or areas within a city, as identified in a higher-level Development Plan or Master Plan. It elaborates on the proposals of the higher plan, providing detailed land use layouts, development control regulations, infrastructure provisions (roads, utilities), urban design guidelines, and specific proposals for that particular zone. This perfectly matches the description "detailed guidelines for physical planning development of specific zones within a city."
(z) (d) Master plan (or Development Plan, Comprehensive Development Plan): This is a statutory plan for an entire urban area (city/town), outlining its overall development strategy, land use zoning, major infrastructure, etc., for a medium to long term (e.g., 10-20 years). While it designates zones, the detailed planning *within* those zones is often done through Zonal Plans.
Therefore, the document that provides detailed guidelines for the physical planning and development of specific zones within a city is a Zonal plan.
\[ \boxed{\text{Zonal plan}} \]