When muliplying these terms you ADD the exponents so
7^0 * 7^4 * 7^16 = 7^(0+4+16) = 7^20 (NOTE you can any multiply when the base number, in this case 7, is the same)
so we simplify to
3^4 * 7^20
---------------
3^2 * 7^12
When dividing we SUBTRACT the exponents so 3^4 / 3^2 = 3^(4-2) = 3^2 and
7^20 / 7^12 = 7^8
so the answer is 3^2 * 7^8 <------- Option J