Find a Pattern from the First 2 Equations of the Following

Multiple Choice

Find a pattern from the first 2 equations of the following sequence of equations and find the missing part of the last equation. ​ 2(4+5+...+15) = 15(16) - 3(4) 2(5+6+...+20) = 20(216) - 4(5) ..... 2( 7 + 8 +...+ 30 ) = ???? ​ ​

A) 30 ( 31 ) - 7 ( 8 )
B) 24 ( 25 ) - 7 ( 8 )
C) 18 ( 19 ) - 7 ( 8 )
D) 24 ( 25 ) - 6 ( 7 )
E) 30 ( 31 ) - 6 ( 7 )