An MIC Result of 10µg of Penicillin for Bacterial Strain $\mu$

An MIC result of 10µg of penicillin for bacterial strain A, 15 $\mu$ g for stain B, 18 $\mu$ g for strain C, and 27 $\mu$ g of penicillin for strain D can be interpreted as the which of the following?

A) Bacterial strain A is more susceptible to penicillin than the others.
B) Bacterial strain B is more susceptible to penicillin than the others.
C) Bacterial strain C is more susceptible to penicillin than the others.
D) Bacterial strain D is more susceptible to penicillin than the others.
E) All strains are equally susceptible.