What do you mean by an execution plan? Why is it used? How will you view it?
a.) An execution plan can be known as a road map which textually or graphically illustrates the data retrieval methods that have been chosen by the SQL
Server query optimizer, for a stored procedure or ad- hoc query.
b.) It is used as it's a very useful tool for a developer to understand performance characteristics of a query or stored procedure.
c.) There exists an option known as "Show Execution Plan" in Query Analyzer. If this option is turned on, it would display query execution plan in separate window when query is run again.