Concept:
A good farm plan should ensure efficient use of resources, balanced enterprises, proper marketing and practical use of farmer experience.
Step 1: Check statement A.
A good farm should have a balanced combination of various enterprises such as crops, livestock, horticulture or other farm activities.
\[
A \text{ is correct}
\]
Step 2: Check statement B.
Efficient marketing facilities are important because production should be linked with profitable sale.
\[
B \text{ is correct}
\]
Step 3: Check statement C.
Efficient use of farm resources such as land, labour, capital, irrigation and machinery is essential.
\[
C \text{ is correct}
\]
Step 4: Check statement D.
A good farm should not use only old agricultural methods. It should adopt improved and suitable modern practices whenever beneficial.
\[
D \text{ is incorrect}
\]
Step 5: Check statement E.
Farmer's knowledge, training and experience are very useful for farm planning and decision making.
\[
E \text{ is correct}
\]
Thus, correct statements are:
\[
A,B,C,E
\]
\[
\therefore \text{Correct Answer is (A)}
\]