(1 point) The table below gives U.S. lead emissions, L, into the environment in millions of metric tons for 1970-1992. Let t = 0 in 1970. Year 1970 1975 1980 1985 1988 1989 1990 1991 1992 Lead emissions 222.4 112.4 47.4 17.9 10 8.3 5.9 5.3 4.6 (a) Find an exponential model for these data. Lead emission, L(t) = 222.4(.87241)^t (b) Find a fourth-degree polynomial model for these data. Lead emission, L(t) = = (c) Which of these curves gives a better model for the data? A. fourth-degree polynomial B. exponential model (d) Estimate the lead emission in 1983 according to the polynomial model in part (b).