Same function in different model

Hi All,

I need to know something about handling the model in optimised way.

Suppose, I have a model (e.g. M1) with 30 functions inside it.  E.g. One of them is A(). I have another model (e.g. M2) with 4 functions inside it. I have loaded model M2 in my controller C.

Now I need to call function A() to do the required task in my controller C. What would be the best optimised way to do this? 

Way 1: Load model M1 also in my controller C and then calling the function A()
Way 2: Create the same function A() in model M2

Looking for reply