Which of Alexander's generals became ruler of Egypt after his death?

Ptolemy I Soter became ruler of Egypt after Alexander the Great died in 323 BC.

Ptolemy was one of Alexander’s closest generals and companions. After Alexander’s death created a succession crisis, the empire was divided among his leading officers, known as the Diadochi. Ptolemy received Egypt as satrap, initially ruling in the name of Alexander’s infant son and Alexander’s half-brother.

Ptolemy soon made Egypt his power base and successfully defended it against rival generals, including Perdiccas. In 305 BC, he adopted the royal title and became pharaoh, founding the Ptolemaic Kingdom. His dynasty ruled Egypt for nearly three centuries, ending with the death of Cleopatra VII in 30 BC.

The other options were also Alexander’s successors, but they ruled different territories: Cassander controlled Macedon and Greece, Antigonus Monophthalmus dominated much of Asia for a time, and Seleucus I Nicator founded the Seleucid Empire. Ptolemy’s dynasty made Alexandria a major center of Greek culture and learning.