5. You are working to determine the TCID50 of an unknown virus which you infected onto MDCK cells. The following table are your results: Virus Dilution Positive Wells Negative Wells Total Wells % infection
10^-1 24 0 24 100
10^-2 24 0 24 100
10-3 16 1 17 94
10-4 9 4 13 69
10-5 4 9 13 31
10-6 1 16 17 6
10-7 0 24 24 0

Using this data, which of the following is correct for the estimated TCID50:
a. The TCID50 is 10^-3.5
b. The TCID50 is 10^-4.5
c. The TCID50 is 10^-3.25
d. The TCID50 is 10^-4.25
e. The TCID50 is 10^3.25
f. The TCID50 is 10^4.25