Task: Question Answering
Input (English): Problem: two alloys a and b are composed of two basic elements . the ratios of the compositions of the two basic elements in the two alloys are 7 : 5 and 1 : 2 , respectively . a new alloy x is formed by mixing the two alloys a and b in the ratio 4 : 3 . what is the ratio of the composition of the two basic elements in alloy x ? 
Options: a ) 1 : 1 , b ) 2 : 3 , c ) 5 : 2 , d ) 10 : 11 , e ) 7 : 9
Output (English): d