What is true about working with burets? 1. you can easily break a buret if it is filled too high. 2. no graduation marks appear above the 0 ml mark. 3. the stopcock will open if you overfill the buret.

I believe the answer is 2. No graduation marks appear above the 0 mL. 
A buret is a piece of volumetric glassware used to deliver variable liquid amounts typically for titrations. It is a long glass cylinder open at one end and fitted at the opposite end with a stopcock valve. The stopcock valve controls the flow of liquid from the cylinder through the buret tip. The numbering of the markings begins at the top of the buret. Therefore, the volume delivered can be determined from the difference between initial and final liquid levels. 

The answer to this problem is. 67

Ido not understand.