1. This object displays the frequency spectrum of real- and complex-valued floating- and fixed-point signals.2.It displays power spectrum as default3.It displays  the psd centred around carrier frequency for bpsk by default4.It plots default between -4 to +4 KHz onlySelect one:a. all statements are correctb. none are correctc. 1,2 is correctd. 2,3,  is correcte. 3, 4 is correct

Without the specific context or the object being referred to in the question, it's challenging to provide an accurate answer. However, the statements seem to describe a Spectrum Analyzer, a device used to measure the magnitude of an input signal versus frequency.

1. Spectrum analyzers can indeed display the frequency spectrum of real and complex-valued signals, both floating and fixed-point.

2. They often display power spectrum by default.

3. The statement about displaying the power spectral density (PSD) centered around the carrier frequency for Binary Phase Shift Keying (BPSK) by default is not necessarily true. This would depend on the specific settings and capabilities of the spectrum analyzer being used.

4. The range of -4 to +4 KHz only is not a standard default for all spectrum analyzers. The frequency range would depend on the specific model and its capabilities.

Based on this, it seems like option c. "1,2 is correct" would be the most accurate answer. However, this could vary depending on the specific context or object being referred to in the question.