Choose the correct answer of the following, explain why it is true, and explain why the other choices are untrue: (A) high pE is associated with species such as CH4, NH4+, and Fe2+; (B) low pE is associated with species such as CO2, O2, and NO3-; (C) values of pE in bodies of water range from about 1 x 10^-7; (D) pE is a number, but cannot be related to anything real, such as is the case with pH; (E) pE uses convenient numbers to express electron activity over many orders of magnitude.