[SunilNagpal]

A: Gram -ve bacteria stained by saffranin
R: Gram -ve bacteria has LPS.

I am assuming that the question was regarding 'which of the two is more correct?'. On that ground, It should be B (Gram -ve bacteria have LPS) as it is due this factor that Saffranin can actually stain Gram -ve bacteria (Saffranin being a basic dye attaches well to the highly negative LPS).

How LPS is negatively charged? BCoz it is phosphorylated and it's the P group that confers the negative charge to LPS.

Edit:
Since it was Assertion and Reasoning, in my opinion, reason is correct.