A protein X with isoelectric point 6.5 was isolated. It was prepared in three different buffers P , Q and R with pH 4.0,6.5 and 8.5 , respectively. With respect to the net charge on protein X , the correct option is

Options

1. ANet charge in P is positive and negative in both Q and R .
2. BNet charge in both P and Q is positive and negative in R .
3. CNet charge in P is positive and in R is negative while both positive and negative charges are absent in Q .
4. DNet charge in P is positive and in R is negative, while both positive and negative charges are present in Q .