Observe the following pattern for obtaining the sums, then find the sum of numbers from 781 to 790?

1+2+3+4+5+6+7+8+9+10=55

A] 7055 B] 7855 C] 7955

Given , 1 +2+3+4+5+6+7+8+9+10 = 55

Now ,  781 + 782 + 783 + 784+ 785 + 786 + 787 + 788 +  789 + 790 

= (780 +1 ) + (780 +2 ) +(780 +3 ) +(780 +4 ) +(780 +5 ) +(780 +6 ) +(780 +7 ) 

+ (780 +8 ) +(780 +9 ) +(780 +10) 

= (780 + 780 + 780 + 780 + 780 + 780 + 780 + 780 + 780 + 780 ) + (1 +2+3+4+5+6+7+8+9+10)

=10 × 780 + 55

=7800 + 55

=7855

So option (B) is the correct answer