Which description correctly explains the deaths of Cassius and Brutus?

Cassius stabs himself due to the information that Brutus has been killed; Brutus is killed by Octavius.
Cassius and Brutus are both killed by Octavius.
Cassius and Brutus are both killed by Mark Antony.
Cassius asks Pindarus to kill him with his own sword; Brutus runs onto his own sword, which is held by Strato.