I agree with interpretation (b).
I read it that further additions may be made to the trust fund by way of:
Further loan;
Settlement (which would include a gift into the trust);
Accumulation of income;
Capital appreciation; or
Otherwise (a catchall to cover any form of addition which the drafter at the time of rafting could not define, or was unaware of)
Paul Saunders FCIB TEP
Independent Trust Consultant
Providing support and advice to fellow professionals