What are the arguments that Spain is immune from suit under the FSIA?

The Commercial Office of Spain hired Enrique Segni to
develop a market for Spanish wines in the U.S. Midwest. The
Commercial Office is an arm of the Spanish government.
Seven months later, Segni was fired, whereupon he filed a
lawsuit in a U.S. district court charging that the Commercial
Office had breached the contract and seeking payment for
the remainder of the contract term as damages. The Com-
mercial Office moved for dismissal, claiming immunity from
suit under the terms of the Foreign Sovereign Immunities
Act (FSIA).
a. What are the arguments that Spain is immune from suit
under the FSIA?
b. What are the arguments that Spain is not immune from
suit under the FSIA?
c. Explain which party should prevail