The first character of ICD-10-PCS codes identifies which of the following?

It is best not to use chlorhexidine immediately after toothbrushing because the positively charged chlorhexidine binds to the negatively charged fluoride molecules in toothpastes

A) Both statement and reason are correct. B) Both statement and reason are incorrect. C) The statement is correct, but the reason is incorrect. D) The statement is incorrect, but the reason is correct.

For an AP knee projection, the central ray is directed to a point inch distal to the apex of the patella. What is the result if the central ray is directed to a point inch proximal to the apex of the patella? 

A. The femorotibial joint will remain open B. The femorotibial joint will close C. Articular facets will appear on end, minimal surface area visualized D. Intercondylar eminence will be shifted lateally