"...the person or body who..." vs. "...the person or body which..."

When referring to both natural and non-natural persons (i.e. organisations) at the same time, is it appropriate to use 'which' or 'who'?

For example:

1.

• '... request the person or body who has the responsibility for this task..' or
• '... request the person or body which has the responsibility for this task..'

2.

• '...the person or body to whom the application was directed' or
• '...the person or body to which the application was directed'

(There is a reason that 'person' precedes 'the body')

Both forms are in regular use. In the example given either would be acceptable, and even referring to a body alone "who" is often used, but probably not in formal usage.

The vagueness over this issue can be illustrated as follows:

In English law there is not necessarily a clear-cut distinction between natural persons and bodies. Some bodies, such as certain professional partnerships, comprise a group of natural persons, and there are natural persons who in legal terms are corporations.

It used to be considered correct form to begin a letter to a company: "Gentlemen,..."

There is a related question as to whether a body should be referred to as "it" or "they". In some circumstances "it" will appear odd; in others "they". Sometimes the fact that what in legal terms is a person is over-ridden by the reality that it is composed of and directed by human beings.