After labelling the figure, we get the following,

• Simplest squares are ABGF, BUHG, CDIH, DEJI, FLGK, GHML,HINM, IJON, KLQP, LMRQ, MNSR, NOTS, PQVU, QRWV, RSXW and STYX (16)
• Squares with four components each ACMK, BDNL, CEOM, FHRP, GISQ, HJTR, KMWU, LNXV, and MOYW (9)
• Squares with nine components each ADSP, BETQ, FIXU, and GJYV (4)
• Square with sixteen components is AEYU (1)

Total number of squares in the figure is 16 + 9 + 4 + 1 = 30

Hence option B is correct.