Which of the following circuits satisfies the logic condition $A=1, B=1$ and $D=1$ ?

In an $n-p-n$ transistor, $95 \%$ of emitted electrons reach the collector. If the base current is 2 mA , then collector current is

The current gain of a transistor is 0.98 . If the transistor is used in a common emitter arrangement what would be the change in collector current corresponding to a change of 0.5 mA in the base current?

In a $p-n-p$ transistor, the current carriers are