According to John Arthur, a reasonable moral code would require us to:

a.
Give money to famine relief when there is no significant reduction in our own happiness, or the happiness of our family.
b.
Give food to our own children first, because they have a negative right to such care.
c.
Give only what we truly desire to give to those who are suffering from famine.
d.
Ignore entitlements and focus only on the consequences of our actions.

To determine the answer, we need to understand John Arthur's perspective on a reasonable moral code. One way to do this is to analyze each option and see which aligns with his view. Here's how we can think through each option:

a. Give money to famine relief when there is no significant reduction in our own happiness, or the happiness of our family.
In this option, John Arthur might argue that it is morally acceptable to help others when doing so does not cause significant harm to ourselves or our loved ones. If this aligns with his perspective, then option (a) would be the answer.

b. Give food to our own children first, because they have a negative right to such care.
This option suggests prioritizing the well-being of our own children, which aligns with the concept of negative rights, where individuals have a right to be free from harm. If Arthur believes in prioritizing the fulfillment of negative rights, then option (b) would be the answer.

c. Give only what we truly desire to give to those who are suffering from famine.
This option implies that giving should be based solely on personal desire, potentially reflecting the importance of individual autonomy. If John Arthur emphasizes personal desires as the basis for giving, then option (c) would be the answer.

d. Ignore entitlements and focus only on the consequences of our actions.
This option suggests disregarding entitlements and instead focusing on the outcomes or consequences of our actions. If Arthur believes that the consequences of our actions should take precedence over entitlements, then option (d) would be the answer.

To determine John Arthur's perspective, it would be useful to refer to his own writings or interviews where he specifically discusses his views on moral codes. Without that information, we cannot definitively choose one option over the others.