A Gaussian(RBF) kernel has this form kyby (X, z) = exp(-| |x - z||"/(202)). Let k(x, z) = (d(x), (z)) be any valid kernel with feature map . Let us try to construct a new kernel out of the Gaussian one, namely we have kybf_mod (X, Z) = exp(-(k(X, X) + k(Z, Z) - 2k(x, z))/ (202)). Which of these statements is true? Hint: How is the Gaussian kernel function defined? How is it built on the underlying Hilbert space? Select one: O a. Krof_mod is only a valid kernel if & is a Gaussian one. O b. Krof_mod is a valid, positive semi-definite kernel for any K. O c. There are cases where Kybf mod is not positive semi-definite