In case of snakebites,the injection given to patients contains preformed antibodies against the snake venom. This type of immunisation is called . . . . . . .

Fill in the blanks: Our body, when it encounters a pathogen for the first time, produces a response called . . . . . . $a$ . . . . . . response, which is of . . . . . . $b$ . . . . . . intensity. Subsequent encounters with the same pathogen elicit a . . . . . . $c$ . . . . . . intensified . . . . . . $d$ . . . . . . response.

Which cells are responsible for the production of antibodies?

Before and after organ transplantation,it is necessary to perform:

Memory cells ............

Given below are two statements.
Statement $I$: Passive immunity is acquired when readymade antibodies are received by body cells.
Statement $II$: Resistance induced by $BCG$ vaccine is an example of passive immunity.
In the light of the above two statements,choose the correct answer from the options given below.