Consider the following statements.
(A) The equivalent thermal conductivity of two plates of same thickness in contact (series) is less than the smaller value of thermal conductivity.
(B) For two plates of equal thickness in contact (series), the equivalent thermal conductivity is given by $\frac{1}{\mathrm{K}}=\frac{1}{{\mathrm{K}}_1}+\frac{1}{{\mathrm{K}}_2}$

Select the correct option.
(a) (A) is false but (B) is true.
(b) Both (A) and (B) are true.
(c) (A) is true but (B) is false.
(d) Both (A) and (B) are false.  
 

• A

  Both (A) and (B) are true.

• B

  (A) is true but (B) is false.

• C

  (A) is false but (B) is true.

• D

  Both (A) and (B) are false.