0.0005 x 10⁻⁴ Farad = 0.000 000 05 Farad.
1 pF = 0.000 000 000 001 Farad
Divide them and get 50000 pF.
The word DoS refers to the Disk Operating System. In the case given above, if it happens that there is a distributed DoS attack, the attacker then sends messages directly to the BOTS. Bots refer to internet or web robots. Hope this answer helps. The answer is the first option.