If you were to round off the measurement 2.33501 grams to three digits, you would get a. 2.33 g b. 2.35 g c. 2.34 g d. 2.36 g

The answer is c. 2.34 g.

Some rules of rounding are:
1. If the number that you rounding is followed by 0, 1, 2, 3, and 4, the number will be rounded down (eg. 0.22 is rounded to 0.2). 
2. If the number that you rounding is followed by 6, 7, 8, and 9, the number will be rounded up (eg. 0.27 is rounded to 0.3).
3. If the number that you rounding is even and followed by 5, the number will remain even (eg. 0.25 is rounded to 0.2).
4. If the number that you rounding is odd and followed by 5, the number will be rounded up to an even number (eg. 0.15 is rounded to 0.2).

So, let's start rounding:
2.33501 is rounded to 2.3350 (rule 1).
2.3350 is rounded to 2.335 (rule 1).
2.335 is rounded to 2.34 (rule 4).
Thus 2.33501 is rounded to 2.34.