Which of the following minerals is likely to be absent in a region consisting mainly of igneous and metamorphic rocks?

Coal is likely to be absent in a region consisting mainly of igneous and metamorphic rocks. This is because coal is formed from the accumulation and compression of plant material over millions of years, which typically occurs in sedimentary environments such as swamps and marshes. Igneous and metamorphic rocks, on the other hand, are formed from molten magma or existing rock that has been altered by heat and pressure, and do not typically contain the organic material necessary for coal formation. Therefore, it is unlikely for coal to be present in a region consisting mainly of igneous and metamorphic rocks.