Why have there recently been fewer opportunities for presidents to cast pocket vetoes?

A) Congress has remained in session virtually throughout the entire year.
B) There have been too many potential override situations as the government has become more partisan.
C) Pocket vetoes must be done in secret, and it has become too difficult to hide any of the workings of the government from the press.
D) Nearly all of the past few presidential pocket vetoes have been overridden, so most presidents are not interested in the potential for failure.
E) Pocket vetoes have generally proven ineffective.

A