Final answer:
Jacob tricks his father Isaac into giving him the blessing meant for his elder brother Esau by disguising himself, following the guidance of his mother Rebecca.
Step-by-step explanation:
Jacob receives his father Isaac's blessing through deceit, as illustrated in the biblical narrative. The correct answer to how Jacob obtains Isaac's blessing is: a. He tricks his father who is blind, following his mother's words. Jacob's mother, Rebecca, orchestrates the deception because Isaac is blind in his old age. She instructs Jacob to disguise himself as his elder twin brother, Esau, who is Isaac's firstborn and traditionally entitled to the blessing. Jacob wears Esau's clothes and covers his arms and neck with goat skins to mimic Esau's hairy skin. When Isaac feels Jacob's disguised arms, he is tricked into thinking that it's Esau and bestows upon Jacob the blessing intended for his firstborn. This act demonstrates the significance of blessings and birthrights in the biblical era and sets the stage for much of Jacob's later life story, as described in the Book of Genesis.