A minimum compressive strength of at least 4500 psi, after 180 days of curing (aging), is specified for concrete used in a bridge deck project. It is further specified that a water-cement ratio of 0.5, a slump of 3.5 in, and air entrainment of 4% are to be used. To provide a curing protocol that will produce the required compression strength, the concrete should first be moist cured and then cured: a. In air for 3 days.
b. In air after 7 days.
c. In air after 14 days
d. A compressive strength of at least 4500 psi cannot be attained.