A will shall be taken to have been properly made if it has been made in accordance with the internal law in force—
(a) in the place where the will was made; or
(b) in the place where the testator was domiciled at the time—
(i) when he or she made the will; or
(ii) of his or her death; or
(c) in the place where the testator habitually resided at a time referred to in paragraph (b); or
(d) in the country of which the testator was a national or citizen at a time referred to in paragraph (b).