Concept:Use a common multiplier to convert the ratio into equations and solve for a.Explanation:Let the common multiplier be k. Then:a+b=6k, b+c=7k, a+c=8kAdding all three:2(a+b+c)=6k+7k+8k=21kGiven a+b+c=14, so:2(14)=21k28=21kk=34​Now,2a=(a+b)+(a+c)−(b+c)2a=6k+8k−7k=7ka=27k​=27​×34​=314​Answer:314​So the correct option is D.