(b) Romans 8:7 the carnal mind is not subject to the law of  God,

(b) neither indeed can be "But  the natural man receiveth not the things of the  Spirit  of God:  for  they  are foolishness unto him: neither  can  he  know [them],  because they are spiritually discerned." (1  Corinthians 2:14)

NOTE  Romans  8:7 from: Romans 3:19,20: These verses  form  a  key conclusion in Paul's argument regarding sin and righteousness. In the previous verses, Paul has quoted the Old Testament to demonstrate  man's sinfulness  (vv. 10-18). The "law" (v. 19), referring to the  Old Testament, was  designed  to silence all mankind under the  conviction  that they have nothing to say against the charge of sin. Likewise, the law was intended to convince all men of their guilt, or liability to punishment, before God.
Paul  concludes  that since all men are guilty,  they  cannot  be "justified"  by their own personal character or  conduct  (v.20). Justification  is a legal term meaning to remove the guilt (liability to punishment) of the sinner. It does not involve  making one  inwardly holy, but merely declares that the demands of  justice have been satisfied. Hence, there is no grounds for  condemnation (Rom. 8:1). Not even obedience to the law can justify  one before  God, Paul reasons, because the very nature of the law  is to prove to man that he is sinful and deserves God's  punishment.
Thus,  the purpose of the law is to lead man to renounce his  own righteousness and trust in the imputation of Christ's  righteousness as the only grounds for acceptance with God.