Who informs congress if the president cannot carry out the duties of the office?

The President
When the President is unable to carry out office duties, he will inform the president pro tempore of the Senate and Speaker of the House in writing and the duties will be assumed by the vice-president until the president is able to resume his duties.

Here is a picture  of the net. its 4 squares in a row diagonal and on the third draw one square aove and under

The answer is b im not sure