The big bang theory is one of the most accepted theories on the origin of the universe because of scientific evidence, such as

1. Red-shift, which is basically the Doppler Effect, but with light. Because stars in other galaxies appear to give off red light, this shows that they are moving away from us (Earth). Red light is on the far left of the Visible Light Spectrum, so things moving away from us appear to be red, while things moving towards us appear blue (the other end of the spectrum). This suggests that the universe is expanding all the time - and therefore it might have started from a single explosion - the Big Bang.

2. Cosmic Microwave Background Radiation (CMBR) has been found by scientists to be coming from all directions in space, and is suspected to be 'left over' energy from the Big Bang.

answer: carbon 14 can only be used to determine the age of the organisms that were once living, and igneous rocks are non living.

explanation:

carbon 14 dating is used to determine the age of the sample by estimating the amount of carbon 14 present in the sample and then comparing it with a reference standard.carbon 14 is a isotope of carbon which is radioactive and unstable. carbon 14 is assimilated by all plants and animals throughout their life from carbon dioxide. however, one the organisms die they stop this assimilation and the carbon 14 content starts to decrease.by knowing how much of carbon 14 is left in an organism after his death, one can estimate the age of the organism. the materials whose age can be estimated by carbon 14 method are the organic compounds. however, some inorganic compounds such as aragonite   shell can also be dated.however, if we consider the igneous rocks it is a non living component which never accumulated carbon 14 in it and thus, we cannot use carbon 14 dating method to estimate its age.