means -
(a) in the case of a mortgage credit asset of a kind referred to in section 4 (1) - 60 days,
(b) in the case of any other kind of mortgage credit asset, or of a public credit asset, substitution asset or cover assets hedge contract - 10 days, or
(c) if in any of those cases some other period is specified by a regulatory notice made under subsection (4) - that other period