57(1.31)^t interpret the meaning of the expression a. the initial number of bacteria is 57 and the growth rate is 3.1% per hour b. the initial number of bacteria is 57 and the growth rate is 31% per hour c. the initial number of bacteria is 131 and the growth rate is 5.7% per hour d. the initial number of bacteria is 131 and the growth rate is 57% per hour