dc analysis is the response of any ckt to the dc supply ip given to it
not only to the dc supply but to any dc source that is selected for simulation purposes
ac analysis there is no dc supply in it all dc supplies are shorted here and the response of the ckt to only ac is studied
That's not correct. Prior to each ac analysis the dc operating point is calculated automatically based on all dc sources in the circuit.
transient is small period of time as above stated if some change is brought about in a time t and then analysing it comes under transient
not only "small period of time". Tran analysis simply is the timely response of the circuit to any selected waveform source.