Answer:
b.  growth in the size of the mineral grains
Explanation:
Non-foliated texture shown by a metamorphic change is depicted by growth in the size of the mineral grains. 
- Examples of non-foliated metamorphic rocks are quartzite and marble. 
- In these metamorphic rocks, mineral grains are not aligned with their long axis. 
- Non-foliated texture occurs under high temperature and low pressure conditions.
- As minerals are able to grow, the size can be used to show a metamorphic change. 
 
        
             
        
        
        
Solar energy will not run out (unless the sun burns out), but the supply of fossil fuels we use is slowly depleting. Burning fossil fuel also releases greenhouse gas into the air, which is bad for the atmosphere.