Remember to incorporate Bimdas, into you calculation and ensure where the addition and subtraction occur you work from left to right.
assuming you mean
where 
ok, notice a pattern in the exponent





hum, so it goes 1,2,3,4, then repeats
ok, so every 4, the cycle repeats
how far up is 77 from a multipule of 4?
4*19=76
76 is 1 away from 77
so 

the answer is B
I hope this helps you
-2a^2b.4.a^5.b^2
-8.(a^2+5)(b^1+2)
-8.a^7.b^3
The area of a kite:
A = d1 * d2 / 2
d1 = BD = 8 units
48 = 8 * AC / 2
48 * 2 = 8 AC
96 = 8 AC
AC = 96 : 8 = 12
Answer: D ) 12 units