PLEASE HELP! Which of the following reactions shows a chemical change producing a solid?

A. H2(g) + O2(g) → H2O()

B. NaCl(s) + NaCl(aq)

C. 2CH2OH() + 302(g) → 2C02(g) + 4H2O(/)

D. 2AgNO3(aq) + CaBr2(aq) + 2AgBr(s) + Ca(NO3)2(aq)

An engineer decides to use a slightly weaker material rather than a stronger material, since she knows that the stronger material can break suddenly. this is an example of what? a choosing a material that will show warning before it fails b using composite materials that combine strength c using a material for multiple applications d using design techniques that increase efficiency and reduce cost