I second this. This is the mainline:
The queen on c7 pressures the file but also x-rays the e5 square, so it has offensive and defensive ideas. In some cases, she can advance to c5.
The knight on d7 is often a piece with a lot of potential as it can advance to c5 to pressure e4, or sometimes Nb6-Nc4 is useful.
That too
I second this. This is the mainline:
The queen on c7 pressures the file but also x-rays the e5 square, so it has offensive and defensive ideas. In some cases, she can advance to c5.
The knight on d7 is often a piece with a lot of potential as it can advance to c5 to pressure e4, or sometimes Nb6-Nc4 is useful.