A statute of the state of Kiowa provided state monetary grants to private dance, theater, and opera groups located in that state. The statute required recipients of such grants to use the granted monies for the acquisition, construction, and maintenance of appropriate facilities for the public performance of their performing arts. The last section of the statute conditioned the award of each such grant on the recipient's agreement to refrain from all kinds of political lobbying calculated to secure additional tax support for the performing arts. The strongest constitutional basis for an attack upon the validity of the last section of the statute would be based upon the 
commerce clause. obligation of contracts clause. Fifth Amendment. First and Fourteenth Amendments.
Question: A statute of the state of Kiowa provided state monetary grants to private dance, theater, and opera groups located in that state. The statute required recipients of such grants to use the granted monies for the acquisition, construction, and maintenance of appropriate facilities for the public performance of their performing arts. The last section of the statute conditioned the award of each such grant on the recipient's agreement to refrain from all kinds of political lobbying calculated to secure additional tax support for the performing arts. The strongest constitutional basis for an attack upon the validity of the last section of the statute would be based upon the 
A. commerce clause.
B. obligation of contracts clause.
C. Fifth Amendment.
D. First and Fourteenth Amendments.
Answer: