Concept:
Richard Serra is one of the most influential contemporary American sculptors, internationally recognized for his monumental:
\[
Site-specific sculptures
\]
His works are designed specifically for the spaces in which they are installed, making location and viewer movement essential parts of the artwork.
Step 1:
Site-specific art refers to artworks that are:
• Created for a particular location
• Designed according to surrounding architecture or landscape
• Dependent on viewer interaction with space
• Difficult to relocate without changing meaning
The environment becomes part of the artwork itself.
Step 2:
Richard Serra is famous for:
• Massive steel sculptures
• Curved steel walls
• Industrial materials
• Spatial interaction
• Monumental scale
His sculptures often force viewers to:
• Walk around the structure
• Experience shifting perspectives
• Feel spatial tension and movement
Thus, the meaning of the sculpture depends heavily on the specific site.
Step 3:
One of Serra's famous works is:
\[
\textit{Tilted Arc}
\]
which became highly debated because removing it from its original site would destroy its artistic purpose.
This strongly established Serra as a master of:
\[
Site-specific sculpture
\]
Step 4:
Option (2): Public Art
Although many of his works are placed in public spaces, his defining characteristic is site-specificity rather than general public art.
Option (3): Installation
His works may resemble installations, but art history specifically categorizes him under site-specific sculpture.
Option (4): Multimedia
Richard Serra is not known for multimedia or digital art practices.
Step 5:
Richard Serra transformed modern sculpture because he:
• Expanded sculpture into architectural space
• Used industrial steel monumentally
• Made viewer movement part of the artwork
• Redefined the relationship between sculpture and environment
Step 6:
Since Richard Serra is primarily known for site-specific sculpture, the correct answer is:
\[
\boxed{\text{(1) Site specific}}
\]