The correct answer is B. 1, 2 and 3.
Glass wool is a type of insulation made from molten glass that is spun into fine fibers. It is used for a variety of purposes, including insulation of buildings, pipes, and other equipment. Glass wool is a good insulator because it is a poor conductor of heat and electricity. It is also fireproof and does not absorb moisture.
However, glass wool is not as strong as steel. Steel has a tensile strength of about 500 MPa, while glass wool has a tensile strength of about 10 MPa. This means that steel can withstand a tensile force of 500 MPa before breaking, while glass wool can only withstand a tensile force of 10 MPa before breaking.
Therefore, the statements 1, 2, and 3 are correct, while statement 4 is incorrect.