A executed a notarized last will and testament instituting only her son B and her longtime friend C as co-heirs to her entire estate, to be divided equally between them. A was also survived by her daughter D. The will made no mention of D whatsoever: she received no legacy, no devise, and no acknowledgment of any kind. After A's death, B and C petitioned to probate the will. D opposed, contending that her total omission from the will annulled the institution of B and C as heirs. B and C countered that D's remedy was merely to demand completion of her legitime, not the annulment of the institution of heirs. Whose contention is correct? (Bar 2026 Syllabus)