The results of a classroom group activity performed to test the acidic or basic nature of two substances are shown in the table.

Classroom Activity Results
Substance Color with Neutral Litmus Paper Color with Phenolphthalein
A blue not tested
B not tested reddish pink

Which of the following is true about the nature of the two substances?
Both substances are acids.
Both substances are bases.
Substance A is an acid, and substance B is a base.
Substance A is a base, and substance B is an acid.