The last one is true.
When multiplying exponents with the same base, add the exponents together.
a) 4^3 . 4^4 = 4^7
b) 5^2 . 5^3 = 5^5
c) 3^2 . 3^5 = 3^7
d) 5^2 . 5^4 = 5^6
Based on this knowledge, a is false as 4^7 does not equal 4^12. B is false as 5^5 equals 5^5, and is not greater than it. C is false because 3^7 does not equal 3^10.
The last one is correct because 5^6 is less than 5^8.