The necessary condition in making of a junction transistor ( E-emitter, B - base and C-collector)

Question

$(a)\;E\;and\;B\;are\;lightly\;doped\;and\;C\;is\;heavily\;doped \\(b)\;E\;is\;heavily\;doped\;,B\;is\;thin\;and\;lightly\;doped\;and\;C\;is\;moderately\;doped \\(c)\;E\;and\;C\;are\;lightly\;doped\;and\;B\;is\;thick\;and\;heavily\;doped \\(d)\;E\;and\;B\;are\;heavily\;doped\;and\;C\;is\;lightly\;doped$