place a cork in the mouth of the test tube. point the mouth of the test tube away from others. hold the test tube loosely with the fingertips. shake the test tube forcefully to keep contents mixed.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: An important rule for students to know when heating a test tube is to
Possibilities:
- place a cork in the mouth of the test tube.
- point the mouth of the test tube away from others.
- hold the test tube loosely with the fingertips.
- shake the test tube forcefully to keep contents mixed.

point the mouth of the test tube away from others.