Main panel: wavelet analysis results by using WWZ for the R-band optical data in the present work. The six Cleanest components were represented by white horizontal dashed lines, with periods of 2.92, 1.66, 1.20, 0.53, 0.47, and 0.24 yr, respectively, from bottom to top. Three possible nonperiodic signals that exist in partial time are indicated by red line segments. The corresponding region of a 47-day QPO that was found by Sarkar et al. (2021) in γ-ray and optical band is marked by a gray line segments, and no corresponding signal was found, possibly because our data were sampled relatively sparsely and very unevenly in this region. Top panel: corresponding R-band light curve observed by us. Right panel: PSD of our light curve.