You Decide to Repeat the Meselson-Stahl Experiment, Except This Time

You decide to repeat the Meselson-Stahl experiment, except this time you plan to grow the cells on light ¹⁴N medium for many generations and then transfer them to heavy ¹⁵N medium and allow them to grow for 2 additional generations (2 rounds of DNA replication) .If the semiconservative model of DNA replication is correct, what is the expected distribution of DNA in the density gradient after two rounds of replication?

A) One band of intermediate density.
B) One band of intermediate density and one band of light density.
C) One band of intermediate density and one band of heavy density.
D) One band of heavy density and one band of light density.